When you go from a 1.5 to a 1.6 it makes your camshaft lift roughly .030 more. Instead of .500 lift it would make it .530 lift give or take a few thousandths. In theory it could make the engine a little leaner or richer but shouldn't make that much of a difference overall.

 

That's a good question. I agree that it depends. If you have an engine with a marginal cam and really high flowing heads and you add lift, you may make the engine more efficient and have to jet up. But if you have a basically stock 350, it probably doesn't improve, or reduce efficiency much, unless you kiss a piston, and then efficiency becomes the least of your worry's.

 

Shouldn't make a difference. I have changed engines under my carb and didn't make a difference. I ran a 548 with a .782/.765 270/278 @.050 and 565 with .814/.798 280/288 @.050. Made 70 more HP and the carb was run the same on both engines.

 

Thanks guy, I actually have a FI engine so I don't want to have to retune if it's close. The cam is a ZZ4 with 475/510 lift and I see where GM uses this cam with 1.6 rockers. I have dish pistons so I may just take the plunge.....