403 Olds any good?

[YaoGuaiCutlass]

Hey all, I have a chance to get a 403 Oldsmobile motor out of a Buick Wagon and was wondering if it would any good for a 1986 Cutlass Supreme? Are they good motors? Can I bump them up to get better horsepower? If so, what's the cheapest route to take? I keep hearing people at car shows saying something about 350 Rocket heads on 403 can make them faster and what-not but I don't know if it's true. Help me out please!

Thanks!

 

[DoubleV]

An Olds 403 is a very good street motor. The blocks are weak, so you can't rev them up really high but if you're just wanting a nice street motor, they are very good.

From the factory they were all low performance emission engines. The stock 4A heads don't flow very well, the cams are very small, the compression ratio is only 8:1 ( probably even a hair lower ), and the tune is calibrated toward emissions and not performance. The point of the 350 heads ( 5,6,7,and 7a ) is that they have smaller chambers so they bump your CR and they flow a bit better. With higher CR, you can get a much better cam. That really wakes these engines up. Put on an RPM intake, a nice exhaust system, and a good tune, and you'll be flying.

P.S. My friend with a bone stock 403 ( even with crappy stock SINGLE exhaust ) ran a high 14 in his 79 Cutlass. He would be mid/low 14's with just bolt-ons.