Oldsmobile V8 interchangeability

-dw-

Greasemonkey
Mar 15, 2021
129
63
Central MN
I'm going to look at a 70 455

What ever you find looking at the timing chain would be ideal. lol

Q-jet 800 cfm is able to satisfy the BB.

I had messed with several different 800 qjets on my 455. Just couldnt get any of them to run better than the ole 750 qjet Ive ran since the early 90s. My 455 does make 425-450 hp and gets 20 mpgs. Ill have long excepted my failure. ha

Imo for a stock ish 455 swap use the w z A-body 442 manifolds.

With some decent compression, cam and head flow iron exhaust manifolds can make some ok power. Up to 2005 iirc I was anti headers. My 84 with x/y manifolds ran best 12.5 in heat. Way back when I found a set of unused Abody sbo headers in the back seat of a car at the local junkyard. Had them in the corner of my garage for like 4-5yrs until I decided to make them fit. It was abit daunting task at first, I realized I couldnt make full lengths so they became shorty or mid length or whatever someone would call them. For being my first set and they turned out pretty sweet. With no other changes my car went to best 12.0 in the quarter. From being anti header I have modified 5 sets of headers to fit my car all in different configurations. I have sets 6-7-8 waiting for some ambition.
 
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zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
expanded my horizons for the time being. figure if im willing to drive a couple hours for a motor, i can try to find a couple other odds and ends on the way. Gas won't be *as much* if i can borrow a buddy's truck for it.

Spotted a 403 that's 4 hours away, running and driving. That's my current #1 right now. There shouldn't really be any issue between that and the 350 right? The 403 is complete, running and ready to drop in. guy wants 800$ which, frankly, is 800$ more than I want to spend right now but it is what it is...
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
6,654
113
Good choice if you can get the 403. It will take the place of the 350 perfectly. Same size externally so all your bracketry and junk will bolt right up. There's a slight amount of differences internally, but nothing to worry about as far as bolting in.

But the 403 will have more inherent power, so you're back to the potential of tearing up stock driveline components if you build it for power. 1st world problems. :)
 
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78Delta88

Master Mechanic
May 23, 2022
315
43
SW Arizona
Spotted a 403 that's 4 hours away, running and driving. That's my current #1 right now. There shouldn't really be any issue between that and the 350 right? The 403 is complete, running and ready to drop in. guy wants 800$...
$800 for running driving 403 is a good price and worth picking up if you can.

350 to 403 difference... Main issue is the Siamesed cylinders and heat. Make sure you have adequate cooling capacity, also suggest separate oil cooler and trans cooler if you're running an automatic. If you are rebuilding, pay particular attention to orientation of head gaskets. Just like SBC 400 and SBF, make sure your steam ports are in the right spot before buttoning down the head.
 
Oct 14, 2008
8,183
113
Melville,Saskatchewan
I agree, $800 isn't terrible if you can see it run and drive. I just picked up a good 403, that was rebuilt at some point for $250. To get the late 70's 800 cfm Qjet to run right with any sort of cam, it needs idle circuit mods.
 
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zipties

Apprentice
Thread starter
Feb 2, 2022
52
18
jeez, felt like i made a big accomplishment today until i came here to post and realized its been about a month lol. I ended up getting my hands on a new-to-me SBC out of an elco for virtually nothing. even included a set of stainless headers.

i've been prepping the garage and the car for the swap and hope to get it done in August sometime. its a busy month already but I guess I'll see what happens.

Looks like I need to do some research on BOP plates if I don't end up finding a trans to go with the sbc. Probably gonna have to buy new which would suck, guessing they're not cheap.

I'm probably going to sell the Olds 350 with all the new parts for pennies. If anyone is interested just hit me up.
 
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78Delta88

Master Mechanic
May 23, 2022
315
43
SW Arizona
If possible I would hang on to the 350. There's another post recently, the OP has 2004r trans.

I have ready source to TH400s but if you could source a 700r that could be ideal. 700r and 2004r getting harder to find.
 
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