Big block install in a G body

Swandog66

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Jun 22, 2020
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I had to modify the lower alternator bracket. I think it’s a perfect example of the big block being taller. After that I’ve been painting the rest of the accessory brackets. And trying to avoid the humidity outside. Not used to humidity in New Hampshire. I also decided to replace most of the nuts on the said brackets with stainless nuts and washers more for rust prevention than looks. A lot of them were partially rounded and really rusty.
 

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Olds 307 and 403

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Oct 4, 2018
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Melville, Saskatchewan
Yes the fit is actually amazingly good nicest headers I’ve ever had. The tubes are 1 7/8” the Fit is better in person I feel the picture makes it look closer in some spots than it actually is.
Good, the set I saw pics of on Classic Olds looked shitty in the ports and didn't fit great on a 75 Cutlass. For their price, they better be perfect.
 

Swandog66

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Good, the set I saw pics of on Classic Olds looked shitty in the ports and didn't fit great on a 75 Cutlass. For their price, they better be perfect.
The ports were nice on mine. They fit much nicer than the last set I had on the 403. These are obviously specific for big block in a G body. I haven’t had to finesse them with a hammer Either. Unlike the last set
 
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Olds 307 and 403

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Oct 4, 2018
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Use the Holley 870 you have, already tuned to your motor. You could add the air flow top to help negate the 2" drop base or cut a hole and add a scoop. I would say a Qjet is on the small side for that monster. Obviously mileage is not this car's main priority, impressive numbers btw.
 

Swandog66

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Yes I thought about the flow thru top air cleaner K&N. I will probably see if my son can fit up in front of the engine with the fan and shroud out to measure the clearance. I’ll probably stuck with the Holley. And I also plan on eventually setting up an A/F meter/gauge to make sure the Holley is tuned properly for street use. And I agree it’s definitely not meant for gas mileage but I also don’t want to wash the cylinder walls with gas running to rich. I just thought I have a videos of the Engine on the Dyno. I’m not sure if I can post videos on here.
 

Olds 307 and 403

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Oct 4, 2018
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Who did the motor for you? You can do a link if you have a You Tube account.
 

Olds 307 and 403

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Good idea choosing someone who knows the BBO.
 

Swandog66

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Ok so it runs and drives but I haven’t made it more than a 1/2 mile so far. Took it out for the maiden voyage and I remembered I had taken off the front license plate so I said I better go back to put it on. So while making the u turn right down the road from the house the power steering belt broke so I went right back because that also drives the water pump. Definitely felt like a beast I live on a dirt road it breaks the tires loose instantly.
 

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Swandog66

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Also another thing a had to do was switch over to a floor shift because the new headers were in the way of the column shift. I really wanted to keep the column shift tI maintain the sleeper look but the way this thing idles with the cam lope I won’t be fooling anyone so I went with the hurst just for the name same as a B&M. Oh and I have a new carpet in my Garage been wanting a new carpet since I got the car.
 

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Olds 307 and 403

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Awesome. Make sure all the spacers are in place and everything is aligned for the belts. I have thrown many belts and broke a few due to alignment issues on Olds V8's.
 
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Swandog66

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yea I believe everything is good the belt that broke was old and not sure how many miles. I definitely should have Gotten a replacement when I got the new longer alternator belt wasn’t thinking straight that day. So I just got back from picking up the new belt. Gonna go install it and take it for a longer drive hopefully. Another thing is it’s amazing how much better serpentine belts are they can last over 100k and never make a noise V belts definitely leave something to be desired.
 

Swandog66

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So I sent my power steering pump back to the rebuilders wore down and broke a second belt. I kept loosing the power assist and the belt would squeal.Going to try to get the new carpet in while the car down with out the pump.
 

Olds 307 and 403

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Oct 4, 2018
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Double check your alignment with a straight edge. Usually belts squealing or breaking is an alignment or improper routing issue. Been there many times with Olds wonderful belt setup.
 

Intragration

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Apr 2, 2019
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Your swap makes me happy. Post some more pics if you can. Will have to read back over it and catch what headers you're using. I had the same column shift interference. It's still tight, but I was able to adjust things and make it work. I was much more urgently going for the sleeper approach.
 
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