Hi guys i have a 74 pontiac lemans sport coupe with an olds455 inside. 396021Fa and J heads which i've heard that they suck. Anws i have a th350 trans and the carb is a rochester quadrajet for an olds350. no idea about gear ratio however.. I dont feel the power of an american muscle knowing that i have rebuilt the engine but did not install any aftermarket parts. Nevertheless..i live in lebanon and i cn't really find an olds specialist.. All i know is that this engine runs about 180hp on the wheels.... My question is how can i reach 300hp without installing alluminium heads ? What modifications can be done.. I would really appreciate your help

 

I moved your post because it had nothing to do with the thread it was in. How did you determine it had 180hp to the wheels? Can you tell us what parts were used in your build, also what exhaust and ignition? What did you use for tuneup settings?

 

I think you have too low a compression ratio, to be able to put in any cam that will make the engine produce 300 hp. I think... :-)
But... getting the ignition and the Qjet set up right will propably feel like a lot more power than you have now. ( please don't spend money on some new carburetor! ) This will not require an "olds-specialist"

 

i didn't put any aftermarket parts . i just did my research and recognized that this engine produces about 180hp . anws what modifications can i do to reach 300 hp? can i reach it without swapping my J smog heads.. concerning olds specialist .. oldsmobile is too rare here each mechanic is givig me a different answer concerning what should be done... may someone plz tell me what modifications can be done? i need some details here plz

 

"oldsmobile is too rare here "
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here, where?

 

Lebanon - Middle East - per his original post.

 

It may only be a low-compression 455, but you should still be able to get some decent performance from it. If the carb is working properly, the first thing you should do is check timing, you want max mechanical advance of about 35 degrees all in by about 3,000 RPM. In doing this, you'll also want to restrict vacuum advance to about 10 degrees max. You didn't mention what kind of ignition you have, but if it's points, you want to make sure that dwell is set properly. Moroso and Crane both make weight and spring kits that would work for you, avoid the Mr. Gasket set. A set of headers and a good low-restriction exhaust will help. With these things you should see a definite improvement.

 

And I will add that a better gear ratio would net you a lot of power.