I am gettin Vortec heads given to me as payment for something and was wondering how much of a loss would I be looking at compression wise and what toll it would have on power. I did a search but found many varying opinions and was wondering if a new concensus had been reached on compression loss

I would like to keep them stock 64cc since I plan on using them on a 350 later on.

Thanks for the info

 

Well, if you have 58cc heads, and swap to the 64cc, then you'll go from 9.3:1 to ~8.7:1.

Now that doesn't mean that you'll lose HP below what you have now. The Vortec heads are so well designed that you normally gain 25-30HP on a typical 350 swap.

I would say you will still gain maybe 15-20HP even though the comp. ratio is dropping. But can you say cheap gas?

The scary part is I've read numerous times that the ACTUAL size of the chambers on the L03 heads is ~55.4.

That would drop you down into the ~8.4:1 range. That is tooooo low. That's more like a late 70's pickup truck. MPG and HP would really kill you then.

I'd say put them on the way they are, especially if you're gonna put them on a 350 later. Then you'll know how you should mod them for your 350, or you may not have to at all. Otherwise you may end up with a 11:1 comp. ratio 350.


G/L,

AJ

 

Thanks for the info AJ. I think I can deal with it that way until I can get a 350,

Thanks again

 

if they were milled to fit the 305 what kinda horsepower would it add? along with my mods plus the ultimate TBI mods and a vortex tbi intake