Intake Manifolds

* 1949 - 1964 * 1964 - 1990 * 1995 - Present

Submit corrections and additions to this information to The Olds FAQ Compiler.

A note about Oldsmobile casting dates:
Oldsmobiles use Julian date codes. All you will see is a number cast into the part from 1 to 365. It will look like a plate with the date was screwed into the mold for the manifolds. Unlike Chevy, which uses actual dates (like 3 C 69, for March 3, 1969), Olds will cast 62 for the 62nd say of the year. For originality and number matching authentication, make sure your julian date codes fall before your car was produced. Look on your block to the pasenger side of the distributor for you block date. Then make sure your manifolds were cast within a few weeks of the block.

[ Thanks to Tony Waldner for this information. ]

Intake Manifolds 1949 - 1964


The early Olds V-8s used a "raised" intake manifold design with a separate valley cover. There was also a small "bug" shield in front of the intake. The later V-8 intake seals directly to the block.


Intake manifolds are cast iron unless otherwise noted.

Casting number and ID are located on top front of manifold, usually on the runners.

ID/   Casting
Code  Number  Year(s)     Application/Notes
      563966  '55 or '56  4bbl. Iron.
      567930              2bbl. Iron.
      571145  '57,'58     371, Tri-carb, 3 2bbl. Easy to spot by the 3 carb holes.
                          Mechanical linkage.
      573388  '5?
      573323  '60         394. 4bbl. Iron.
D2    580676  '61         394. 2bbl. Iron
D3    382856  '64         394, UHC 394. 4bbl. Iron.
      382855              4bbl. Iron.

1954 and 1955 324s' have smaller intake ports and valves than the 1956 engines. 1955 and earlier four barrel intake manifolds won't fit a 1956 engine unless you put a dent in the lifter valley cover. 1957 and later cylinder heads will physically bolt on to 1949 to 1956 engines, but the port matchup on intake maniflolds will be off because different cylinder deck heights are used. 1957 and later cylinder heads have larger coumbustion chambers and valves.

J-2 Intake Details

First off the J-2 will have "571145" cast in the front.

Secondly, the throttle plates of the appropriate 2-Jet carbs were small, about the size of quarters, the later 2 barrel throttle plates (and appropriate holes in intake) were visibly larger from about 1965 and after.

Further, this intake will only bolt onto the Oldsmobile 371 CID engine made from 1957-1963 due to clearances with cylinder heads and block.

Further, a special vaccuum linkage was used to allow the end carbs to go from closed to WOT at 68° throttle opening on central carb. Central carb provides all fuel for idle and off-idle!

Lack of this vacc system will require a jury-rigged mechanical linkage, if you can scrape up the carbs at Ye Olde Junque Yardes. There are 371's lying fallow. Just gotta find them!

I have this intake, a 371 lined up, and one of the three carbs rebuilt. I will still need the appropriate jets, and some form of linkage that staggers carb opening to eliminate the bog of both ends opening at once.

The J-2 intake fits 371cid blocks and 1957-58 heads ONLY. Have heard of it being adapted for similar applications, but Karl is reluctant to perform non-reversible operations on antiques.

The J-2 intake is a dual-plane intake that used a vacuum-actuated linkage. The center carb provided all idle and off-idle. At a centre carb throttle plate angle of something like 68' (degrees) the vacuum linkage would actuate, and open the end carbs, which operate at WOT only.

The linkage, if complete, is worth more than the bare intake, but probably not as much as a set of correct end carburetors. Not to mention air cleaners, or correct Air cleaner shroud (covered all three).

2GC uses an integral choke, while the 2GV uses a vacuum-break choke. The choke is actuated by a small diaphagm connected to steel tubing that disappears in the area of the exhaust manifold.

Not positive about functionality/routing of tubing.

The Original J-2 carbs are 2x2G (ends) and 2GC (center). These are, again, the small throttle plate variety.

[ Thanks to Karl Aune, Joe Padavano, [email protected], Ryan, Scott Clark for this information ]

Port Sizes

Intake Length Width Area (approx.)
J-2 1.88" 1.19" 2.23"

[ Thanks to Karl Aune for this information. ]

Intake Manifolds 1964 - 1990


Basic Olds V-8 intake. This is an aluminum smallblock intake, a big block would be just a little wider (see explanation below).


The 'Number=SB, Letter=BB' coding extends to intakes, too.

Usually, the big ID [not the 6-digit ¼" tall all-number ID] letter or number will be found near the front, often down in the depression between the front fuel/air runner and the front water passage which contains the thermostat. In other words, behind the thermostat's front right water passage and the #8 cylinder's runner. Usually on the right or passenger side of the intake.

The casting number is a 6 to 8 digit number, usually on one of the intake runners, often behind the carb, and usually near a raised CFD and star (dot with radiating lines). Not to be confused with the 8-digit firing order, which is always 18436572, and usually marked with the words "FIRING ORDER". Each runner has a raised number corresponding to it's cylinder number cast into the top surface of the runner.

There's a casting date code on the underside of the manifold, on the heat crossover.

The thermostat cover/radiator hose has a special molded in bypass pipe for the waterpump. Two bolts on each side, one left, one right.

With the thermostat cover removed, Olds intakes have a circular thermostat hole with an elongated U shaped hole facing toward the front of the intake.

These intakes seal directly to the block. They are not raised, using a seperate valley cover (not to be confused with valley tray). Typical thermostat housing front and center. This uses the distinctive gasket with one large hole (for the t'stat), two opposed bolt holes on either side, and the bypass hose hole in the front. This is, and the letter/number usage is the dead giveaway for id.

The thermostat on the 1966 L-69 3x2 Tri-power manifold is further forward than on other Olds V-8s, due to the need to clear the front carb, and thus uses a unique molded bypass hose for this application. It also uses a pair of roughly square covers, one on either side of the center carb, bolted to the top of the exhaust crossover passageway. Each cap should have four bolt holes, but only be held on with two bolts. These are the exhaust crossover blockoffs on the 1966 manifold.

Pre-smog intakes are said to flow about the same. Easy to spot - no EGR valve or place to attach one means it is a pre-smogger intake!

Note that Toronado units had very low rise intakes. This might be an advantage if hood clearance is more important than all-out power generation. Toronado's from 1966 to 1970 had the very low intakes. I know of no substitute which allows for a stock hood height.

The 1968-9 "J" 4V intakes used a carb whose choke coil was 'divorced' or mounted in a cavity (sort of a divot) in the intake, rather than the round black choke coil mounted on the carb as later applications used. A divorced choke is a recess in the intake on the passenger side of the intake. This choke has a sort of squarely bent metal covering. This remote choke coil is VERY expensive, about $75, so unless you need it for originality or can work your choke some other way [later model, hand, electric...] you might want to avoid USING that manifold. It still makes a nice way to identify a 1968 to 1969 Olds engine. As long as its choke coil still works, no problem.

1965 was the only year for the square bore (i.e. non-Q-Jet) intake manifold for the 400/425 big blocks. In theory this would fit any square bore carb. Some very late 1965 model year engines used a Q-jet.

A solution to run a square bore Holley on this manifold is to use an adapter plate which can be found for about 25-30 bucks in most speed shops. It does exactly the job you're looking for, but get a few extra gaskets just in case this more-complex-than-stock setup generates vacuum leaks.

[ Thanks to Chris Witt, Joe Padavano, Chris Fair, Bill Culp, Mark Prince for this information ]


Intake manifolds are cast iron unless otherwise noted.

ID/   Casting
Code  Number  Year(s)  Application/Notes
B     384439  '65      400 4V All. Square-bore carb mount. Iron.
C     387958  '66      425 4V Toro. Spread bore carb mount. Divorced choke.
E     390390  '66-'67  400/455 Including 4V W-30. Early 400, other BB's
                       except Toro up to 68 or 69 or so. Iron.
F     393238  '66      400 L-69 3 x 2. Easy to spot by the 3 carb holes.
                       A pair of roughly square covers, one on either side
                       of the center carb, bolted to the top of the exhaust
                       crossover passageway. Each cap should have four bolt
                       holes but only be held on with two bolts. These are
                       the exhaust crossover blockoffs. Iron.
G     397357  '67      425
J     398662  '68-'69  400/455 4V All including W-30 and 68 H/O. Except Toro,
                       69 H/O. Iron.
K     398664  '68-'69  455 Toro.
?     405233  '69      455 H/O. Very rare, obviously. Only 1 application. Features
                       a provision for the pcv valve directly in front of the carb
                       (in a hole behind the coolant crossover, similar to the
                       arrangement used on the aluminum 70-72 W-30 intakes). Iron.
?     406115  '70      455 W-30. "Oldsmobile W-455" in raised letters.
                       Aluminum. "Olds W-455" on some.
L     404521  '70-'72  455 4V AT and MT. W-33, 442, SX, 88, 98's. Except W-30. Iron.
P     407568  '71      455 2V AT. Vista Cruiser. No EGR. Iron.
S     407569  '70-??   455 4V Toro. Low profile. No EGR. Iron
R     407567  '70-'72  455 4V MT except W-30. No EGR. Iron.
A     407570  '71-'72  455 W-30. "Olds W-455" cast in raised letters.
                       No EGR. Aluminum.
U     410448  '72      455 4V except W-30, alternate to R for '72. Iron.
H     388625           2V. Iron. EGR.
X     412493  '73-'76  455 Toro. Iron. EGR. "OLDSMOBILE" cast in.
W     412753  '74      455 4bbl L-74, L-75. Iron. EGR. "OLDSMOBILE" cast in.
Y     411990  ??       ??. EGR.
Y     413111  '73-'76  455 All models, GMC motorhome. Iron.

?     381920  '65      330 1V. Iron.
?     398663  '68-'69  350 2bbl. Iron.
?     406114  '70      350 4V. W-31 only. "OLDSMOBILE W-350" cast in.
1     407571  '70      ??? 350 W-31. Aluminum. ??? (need to verify)
6     390327  '66      330 4V. Iron.
8             '65      330 2V. Iron.
10    404520  '70
      398583  '70-'71  350 2V. Iron.
      407564  '71      350 2V. Iron.
12    407565  '71      350 4V. Iron.
      4085520 '71      350 4V. Iron.
13    410670           2V. Iron.
14    410446  '72
16    411880  '74-'77  350 all 4V. 88's. Iron. EGR. Raised letters
                       "OLDSMOBILE" (5/8") on runner
      1606818 '75-'79  350 2V port injected EFI. Aluminum. EGR.
17    22503087         4V. Iron. EGR.
                       for #1 and #4 cylinders. '77 has no letters. Iron. EGR.
A1    N/A              2V. Aluminum. EGR. Small ports. No casting number.
A2            '81      260, maybe 307. Aluminum. EGR. 2bbl single plane, ~1 3/8" barrels.
                       Small ports. Some have no casting number.
A4    22504086'82-'85  307 4V. Aluminum. EGR. Large ports.
A5    22528212'85-'90  307 4V. VIN Y engines, not VIN 9 engines. Aluminum. EGR.
                       Small ports.
      22500203         Diesel. Iron. No EGR. Machined 3 1/3" opening
                       at the front for the injector pump.

      EA18743 '69      Experimental W-30. 4V. Aluminum. Divorced choke.
A     ER-13112         Experimental.
      3ER-38086        Experimental 350 CFI (central fuel injection). 2V.
                       Aluminum. EGR. 3 bolt holes at base for injection unit.
                       2 bolt hole towers toward rear of manifold.
[ Thanks to Chris Witt, Ed Ekstrom, Joe Padavano, Rich Scott, Kevin Hoopingarner, Graham Stewart, Mark Prince, Jim Chermack, Kevin O'Brien, Greg Pruett, Dave Carolfi, Jason Adcock, Greg Rollin, Mark Weinberger, Josh Brown, Steve Harrison, Charles Dempsey, Michael Ecker for this information ]

Intake Height

The height on a stock 455 intake is 2 3/4", a Toro intake on a 455 is 2 1/8". The Edelbrock Performer BB intake height is 4 1/2".

[ Thanks to Chris Miller for this informaiton ]

ER-13112 Detail Description

It is configured for two QuadraJet carbs oriented back-to-back with the primary bores pointing towards the rocker arm covers. A bellcrank linkage arrangement operates the two carbs' throttle levers. (I was convinced that the manifold I bought was a factory-built experimental unit because no aftermarket company in their right mind would cast such an intake using Q-Jets instead of Holley carbs!)

The manifold itself is aluminum and uses a pair of rather large plenums with straight individual runners to each cylinder. Each runner has a raised number corresponding to it's cylinder number cast into the top surface of the runner. Other identifying nomenclature on the manifold are the words


cast into the forward edge of the top of the left (driver's side) plenum and the serial number

ER-13112 -A-

cast into the left side coolant passage (between the left edge of the manifold and the t-stat housing). All of the letters noted above are about 1/2" to 3/4" tall and raised.

One interesting thing about the intake is that a standard Olds points distributor will not clear the intake (and the HEI is even larger). Use of this manifold will require either some sort of custom-fabricated distributor which is taller, offset, or smaller in diameter, or else the engine will need to be run using a distributorless ignition system similar to that used on the Aurora engine.

I can't imagine that Olds made more than 8 or 10 of these intakes, so if it really is one of the factory experimental manifolds it would be worth a lot.

[ Thanks to Joe Padavano for this informaiton ]

Later Aluminum Intakes

As for intakes, the 260 always had the 2V or psuedo-Qjet. With aluminum 4V intakes, I remember the diffs as "5 is jive, 4 gimme more." Hokey, but with my memory, it works. The A5 4V intake has the girly ports, whereas the A4 has the larger ports which would match well with, say, a 403 head, etc.

[ Thanks to Chris Witt for this information. ]

Aftermarket Intakes

Threads, vacuum ports
The manifolds come with threaded ports you may or may not need. Cap accordingly. You may need to find caps or bolts to fit. Just make sure you know which type of threads they are. For example, pipe threads for water jackets. Intake runner ports are normally pipe thread too. Mounting bosses usually use straight threads.

Using with OAI
You can use the OAI air cleaner on the Edelbrock Performer intake. My fellow Oldsmobile Street Rockets are currently using this configuration. The secret is to take the OAI lid with the functional door, turn it upside down and remove the rubber seal thats connects to the air cleaner base. If you remove the rubber, it gives you about and inch to inch and half clearance. Thats just right for a HEI distributor and the Performer intake. If you have any questions email some of the members of Oldsmobile Street Rockets at

There are fellow performance enthusiasts on this page, and we have tried all the combos with intakes. Performers, Torkers, Dominators, Performer RPM's, O4B'S, Port-o-sonics, tri-power, dual quad, Batten sheet metal, and so on.

[ Thanks to Mike Rothe, Mark Prince for this informaiton ]

PCV Valves

The OAI intakes on all 455s from 1970 to 1972 have a pressed in fitting in the intake for the PCV. The hole for the fitting is open to the lifter galley. The fitting is approxiamately 1" to 1 ¼" high, and sticks up about 7/8".

On non OAI cars this same arrangement was used on four speed cars with iron intakes, while automatics had the PCV in the left valve covers. The fitting is also used on aluminum W car intakes. 4 speeds used this arrangement because the air cleaner was dual snorkle, and so the PCV went from the intake to carb.

A 90° rubber nipple goes between the fitting on the intake and the PCV valve. A short hose goes between the PCV valve and the base of the carb. This set up allows the use of two breather tubes between the air filter and the valve covers for better crank case breathing.

The GM part number is 405143 (description NIPPLE, ventilation (steel-1 ¼"). In addition, this was used (according to my parts illustration book) on many applications including, but not limited to, '69 H/O's, '70-71 OAI w/AT or ST, & all '72's with OAI and or ST, 73 A-Bodys w/ST, and 73 A-Bodys w/L77 and M40 AT.

[ Thanks to Dave Wyatt, Mark Prince, Kevin Hoopingarner for this information ]

EGR Injectors

Over time the EGR injector tubes at the bottom of the intake manifold bores become clogged with carbon, and result in engine pinging that cannot be tuned out without a good loss of power. The carbon must be cleaned out to get rid of the pinging and tune the engine properly.

Remove EGR, remove carb, get a 3/8" or 5/16" drill bit and drill through the EGR tube extensions gently down till hit the manifold floor. Olds and Cadillac (from the 4.9L V-8) do not recommend you removing the EGR Tubes. I have seen them ready to fall through the manifold floor, so if you choose to, be cautious. If you can, run a piano wire through the tubes till it comes out of the EGR valve mount. Run it around and try to get as much clear as you can. I did not have the piano wire, I just blew out the carbon buildup, and reassembled. Mine runs great now. I did this on my 1985 307, and on the junkyard A4 intake I bought (from 82 307). After 6 months after I cleaned the 1982 intake, I removed and there was a small amount of carbon building up again. Not enough to restrict flow, but enough to warrant a 2 year cleaning interval (probably your own 30K EGR service).

The 307 engine is very sensitive to EGR flow, even a 50% reduction is enough to cause pinging headaches. Your car should run fine on 87 octane fuel. Mine with 50% blockage still pinged on 93 octane. With the timing set a 20 degrees as factory specified.

Do not use oven cleaner, it is caustic and will erode the aluminum intake manifold! Use the above procedure, it is best and last longer than any cleaner can do!

Do not fear removing carb, tag everything, take your time. You will have it off in about 30 minutes. DO get a line wrench, 5/8" and �". The 5/8" I would call mandatory, the �" is optional. The rear vacuum line is the �".

When done, torque the carb to manifold no more than 16 ft lbs., I think 10-16 ft lbs. is spec. You can easily warp the carb beyond use by not heeding this! Also, Olds recommends retorqing the carb every 6 months in the 1976 Olds Service Manual.

[ Thanks to Thomas Martin for this information. ]

Filling the Exhaust Crossover

I melt old cast pistons in a flea market cast iron skillet. I lay the head intake side down on a steel plate, and preheat the head to 150° F. I pour the molten aluminum into a little fixture [trough] made from 1X1 angle iron that I stick into one of the bowls. I pour it in until it runs out both bowls. I've done several sets of heads, and the cast aluminum has held up well, even on daily drivers.

On a former daily driver [79 toro w/77 403] I wanted a little heat for the carb, so I inserted a piece of 1/2" e.m.t. [conduit] into one of the bowls on one head. I stuck the conduit down through one bowl, and let it stick up out of the bowl, while i poured through the other bowl. Once i poured, I was able to grind down through the aluminum on the intake side, and find the end of the conduit. A bit of grinding was needed to cut of the section sticking into the bowl. This way I had a little heat from one exhaust port going to the carb area.

On my 64 Cutlass[461"] I cut my exhaust side back .175". This was enough to create a gasket area apx .125" wide between the center ports.

Optional -You can also grind the roof higher until you have only about .1875" from the top of the port to the top [outside] surface of the head. This makes it harder to match the header, but it will help flow, as it takes some of the downhill slope out of the roof. You can slot the bolt holes on the header with a die grinder, or weld them shut/redrill to raise the header up to help the port match the header.

BTW, Dave Smith once told me that pouring the heat risers and cutting the exhaust side back/raising the roof is worth 40 hp on a 455. The best part is it gets rid of that sh*tty Olds/Pontiac exhaust sound.

[ Thanks to Dave Brode for this information. ]

Port Fuel Injection

Port fuel injection was available on the 350 Olds motor used in some Cadillacs. 1975 ½ to 1979 Eldorados, and California emissions equipped 1980 Sevilles and Eldorados. Unfortunately, there is no stock big block FI intake. You might be able to make one fit with adapters to compensate for the added deck height.

It had a port injected manifold. The system used a manifold that was basically the same as the carbureted version. The manifold was a very low profile, dual plane type; sort of like a Weiland X-cellerator, but much flatter. Looks like it should flow pretty good for a mild street motor. The major differences being the injectors mounted in the ends of the ports and a hole in one of the ports at the front of the manifold for an air temperature sensor. The throttle body looks like somebody cut the top off a two-barrel carb.

It has no heat riser and it looks to be a special casting to accomodate the fuel injectors. It has 8 fuel injectors, 2 are mounted at the end of each runner, each injector feeds an individual intake port. There's a copper-looking fuel rail that feeds all the injectors. The injectors look pretty standard issue, nothing special. I understand that there were some aluminum EFI manifolds produced.

It has EGR. The valve is mounted in the same place as any of the Olds engines. Four bolts hold down the throttle body. The diameter of the barrels on the throttle body are 2.25 inch, the same size as the secondaries on a mid 70s vintage Q-jet. The mount on the manifold for the throttle body is about 4 inches square, and there's two round holes in the middle that match the barrels. The hole that the throttle body mounts over is bigger than most 2bbls and smaller than a 4bbl. The ports that mate to the head are about 1.25 inch by 1.9 inch. The throttle body was manufactured by Bendix, as was the fast idle valve. The TPI sensor is Bosch and has a 5-pin connector (actually 5 spades, not pins).

The electronically controlled, 2-phase Bendix, fuel injection system provided 180bhp @ 4400rpm, and 275lb-ft @ 2000rpm, slightly more than the carbureted version, mainly due to cooler manifolding. It was reported that this engine was able to meet emissions standards without a catalytic converter, but was so equipped nonetheless!

The computer was an analog unit that was located in the center of the dashboard. It was a regular Olds 350, with a different PFI intake and distributor. They were very often converted to carbs because the system did not run well at times, and was also known for catching on fire, due to some questionable rubber hose used for the pressurized fuel line. For anyone with one of these cars, convert to today's FI hose!

The ECU's for these port injection systems didn't place any programming in removable EPROMs. For instance, Cadillac used a different ECU for each body style to help tailor throttle response characteristics.

Fuel delivery started with two fuel pumps; one in the tank; one further up the line. From there, the fuel was pumped through the injector banks and to the fuel pressure regulator. The pressure regulator kept the pressure at 39 psi. It was attached to manifold vacuum, so, apparently, that had something to do with regulating pressure. From the pressure regulator the fuel ran back to the tank. The fuel injectors were solenoid operated pintle valves. The ECU signals them to open for precisely the right amount of time to meter the fuel needed by the engine. Air delivery was provided by a throttle body and a fast idle valve.

The system was most likely bank fired (4 at a time). There was no crank sensor, so it couldn't be sequential. There was a sensor in the distributor housing that indicated 1 pulse per 1 rev of the distributor. It was a closed loop system; about as good as an analog FI system gets. The system is covered in several books that relate to automotive electronics/history.

The system had pretty much all the standard sensors, except for a mass-airflow sensor or oxygen sensor. It had a manifold absolute pressure (MAP) sensor, so mabye that was used in place of a mass-airflow sensor. This along with the bad temp. sensor location may be why the system had a reputation for running lousy. The system also used a throttle position switch, and air and coolant sensors. The air and coolant temperature sensors are identical and completely interchangeable. There was an engine speed sensor in the distributor. This sensor consists of a plastic housing containing two reed switches and a rotor with two magnets. The ECU uses the opening and closing of the switches to synchronize the fuel delivery and to monitor engine rpm. The distributor was unique to the EFI, and a regular distributor won't work with the system. The ECU is serviceable only by a Cadillac dealer according to the manual.

he throttle body is not just an adaptor for the aircleaner, it uses throttle blades to regulate air flow into the engine just like a carb would. It also houses the fast idle valve and a Bosch throttle positon sensor. It also has a buncha vacuum connections for the usual accesories; vacuum advance, power brakes, PCV, etc. It takes a standard 4-bbl air cleaner but it has a spacer so that the air cleaner will clear the HEI and the fuel rail.

One of the biggest design flaws was mounting the intake air temp sensor in the manifold where it was affected by heat from the EGR valve and cooling system - not good. These cars didn't tend to run that good.

If reusing the original 70's ECM, you would need the PFI dist - the distributor is unique to this analog ECM. It's been verified from several people that the output from the 7-wire module is the same as the module from a TPI distributor, so a GM TPI ECU could be used. Fortunately, the ECUs didn't control spark, so if the 350 was rebuilt with a higher compression ratio, it would be a relatively simple task to recurve the mechanical advance and install an adjustable vacuum advance unit.

One would probably be able to use any GM V-8 (firing order 18436572) TPI (not SFI) ECM (to start with, then roll your own, or use some other aftermarket Chevy TPI setup. To my knowledge, the TPI (85-89 at least) system just does 1 bank on one spark pulse, and the other bank on the next.

The beauty in the TPI ECM - since it is NOT sequential (injectors fire one at a time in relation to each cylinder), there doesn't need to be any device to determine TDC of cylinder 1.

Also, it's been said that sequential will only really be a noticeable advantage over bank at low speeds. Much above 3000 rpm the difference is negotiable.

Now for some speculation on performance potential. The ECU apparently cannot be serviced and is pre-set for the (smogger) engine setup, a 180 net HP 350. I think it might be possible to "dope" the inputs to the ECU so that it alters the mixture accordingly. For example, playing with the temperature input reading so that the car runs richer. The only problem is the ECU probably has preset ceilings for how much fuel can be injected, so the engine would likely lean out at higher rpm.

Another idea I have, which I think is more viable, is to use some sort of adjustable fuel pressure regulator to increase pressure so that (hopefully) more fuel will be pushed through the injectors across the rpm range, and you could "jet" the engine by adjusting the fuel pressure. This would be limited of course by how much pressure the lines and injectors could withstand.

Another problem with the system is the fact that it used a two-barrel manifold. A throttle body will flow more than a carb of the same size but I have my doubts whether the throttle/manifold setup could flow much more than 500cfm. It may be possible to mount injectors and sensors in a high-performance manifold and use a Cadillac ECU, but I doubt it's worth the time and expense.

If you are looking for one of the above cars with this setup, they usually had an "Electonic Fuel Injection" badge on the fenders and grille. Ask around at some repair shops.

[ Thanks to Kevin Wong, Greg Pruett for this information ]

Port Sizes

ID Intake Length Width Area (approx.)
'76 BB 2.28" 1.22" 2.782"
A4 '82-'851.30" 2.03" 2.639"
A5 '85-'901.30" 1.30" 1.690"

[ Thanks to Karl Aune, Jason Adcock for this information. ]

W-30 Intakes

Although I do not have an answer as to the reason for the two 1970 W-30 intakes, the broken mold at Winters sounds like a logical explanation. As near as I have been able to document, the manifold (406115) changed from reading OLDSMOBILE W-455 to OLDS W-455 in early December of 1969.

The earliest OLDS W-455 casting date (located on the underside of the manifold on the exhaust cross over) I have found is 12-5-69. It seems they made a whole slew of them in that time period. As the overwhelming majority of (406115) OLDS W-455 have casting dates between 12-5-69 through 12-11-69. These were in use on 1970 W-30's sometime shortly thereafter. As to a specific date for the on-car change, I couldn't say for sure. Although I have not personally encountered an original 1970 W-30 built after February that didn't have the OLDS W-455 intake. So your April 1970 W-30 with the early OLDSMOBILE W-455 lettering is a bit of a mystery to me.

Cars built after 3 Jan 70 should have the OLDS W-455 intake. We have never seen a December BUILT car have one. The earliest casting dates are in the mid December time frame. The Early OLDSMOBILE W-455 intakes are some of the hardest to locate. We have also seen date codes as early as 13 Aug 69 on the Oldsmobile intake.

[ Thanks to Greg Rollin, Jim Chermack for this information. ]

Intake Manifolds 1995 - Present



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