Hello, I have a 71' 318, all stock. I'm pretty sure the comp. is 8.6:1 and the HP is 230. I was wondering if I got the heads shaved and bumped the Cam up a little, how much difference it will make. I want to stay with the 2 bbl carb. I'm wondering what else I can do for some better performance other than change it to a 4 bbl, or rebuild the engine.

Jay

 

why dont you want to change to a 4 bbl? depends how much you shave the heads. and how big of cam? with that comp ratio or even 9.0 and a healthy cam 30 hp? off the top of my head. you can add up to 15 hp with the right 4bbl tuned properly

 

Don't forget that a motor that has the carb, intake and cam to take in nice, deep, powerful breathes of air/fuel, need a way to exhaust them as well. Maybe think about about a full exhaust system (doesn't have to loud) to help it breath better and get much more power with what you want to do.

 

Jay -

Sorry, but with a stock motor, including heads, intake, carb and exhaust all a "bigger" cam will do is possibly make more noise and give you more headaches (read - minimal performance gains).

Think of it this way, the cam is trying to suck in and push out more air. The intake (carb and manifold) and exhaust (manifolds and pipes) can only handle so much. You sorta want to assume that the Chrysler boys tried to figure out a pretty decent match of components - playing with that, will usually just mess things up. Does that mean you "can't" just change the cam? No, just not a great idea, IMHO.

Best bet would be a staged approach, changing those three components as your budget allows.

Archer

 

Thanks guys, I'll probably just drive the car stock for now and put the money into the 413 i'm thinking about putting in. This 318 a good running engine, I drive it alot and wanted to keep some kind of realistic gas mileage.

 

Better fuel economy with a 4 bbl as well.
Smaller primaries.

 

YES!!!!

 

413 is cool but kinda a small bore...if i had to choose a big block. either a 400.. with a forged 383 crank.. or a 440