Just curious, what country are you located. Also what happened to the 4A heads it probably came with?
OLDS Olds 403 with new CAMSHAFT fitment?
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when i got the engine it had the 5A heads on it . i also found a pair of 4A heads but i dont think that going from 5A to 4A make any difference for me !?Does it ?
The 4A heads flow better on the intake side but have huge 83+ CC chambers, mine measured 86cc and suck almost as bad as your 5A on the exhaust side.
Well, late 5A are designed to support 307 cubic inches where the 4As were designed for the 403. So, there's that.
There's always the aftermarket head route. Bottom line, that cam needs better heads either way.
That's the 1st 403 I have seen grenade. I ran mine hard and without a girdle for years but never had a problem. It was built correctly (line bore, balanced reciprocating assy. etc.) so perhaps that helped.
It's time for Marcar to upgrade to an LS. No more oil leaks or worry about puking the bottom end out on a highway merge....
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No LS! The 4" stroker Olds 350 is a sweet package, much less reciprocating weight, strength and smaller journals for less bottom end failures than a 455. Definitely better low end torque than an LS and more than acceptable 400 to 500+ hp. I am building a 403 because I have the parts, stroked 330 crank included, mine is an auto and won't see past 5500 rpm. Hopefully it will live a long life.
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It'll go 6000, just not often...
I often wonder how much my 468 bottom end will hold. I just can't afford to test it.
The 455 can rev but everything needs to be right. I just think a 350 with more stroke, along with billet and forged parts will rev along with major torque. There are many more 455 bottom end failures than the 350, I think parts weight and bearing size are the main reasons.
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