64cc are better for a blower stup...58cc are better for NA setup...If you were going to put 64cc on a NA motor they would make about 5HP less than the 58cc ones...compression ratio really has to do with the pistons and if you change them to high compression or low compression...heads only do a fraction in terms of compression...You generally want low comprssion like 8.5:1 for blower application and about 10.1:1 for NA and still keep it streetable...Hope this helps...
Exactly, quench area, and compression. Milled heads are good for NA, and are also good for power adder, to a certain point. Mill them too much and you have issues..
Another thing to take into account is the pistons, valves, pushrods, rockers, etc. The whole valve train must be in sync. If you mill the heads down, run a large rocker, large cam, and flat top pistons you run the risk of piston to valve clearance, and we all know when they meet, nothing good comes out of it. 58cc is usually fine, but you always want to be 100% sure.
Ideally you want as small a chamber as you can get away with because there will be less heat lost into the cooling system and for the larger quench area. Like I said, this is merely an ideal. If you want to put heads and a blower on your 5.0, then you should probably get 64cc chambers to lower the compression. Not only that, just about all aftermarket 64cc chamber heads have enough material to be safely milled down to 58cc. On the other hand, if you want to put heads on a N/A engine, then 58cc will make more power by raising the compression.
If I was going to use a blower/turbo, I would get 58cc heads and dished pistons.
Ideally you want as small a chamber as you can get away with because there will be less heat lost into the cooling system and for the larger quench area. Like I said, this is merely an ideal. If you want to put heads and a blower on your 5.0, then you should probably get 64cc chambers to lower the compression. Not only that, just about all aftermarket 64cc chamber heads have enough material to be safely milled down to 58cc. On the other hand, if you want to put heads on a N/A engine, then 58cc will make more power by raising the compression.
If I was going to use a blower/turbo, I would get 58cc heads and dished pistons.
yep thats what i built, a low compression 347 shortblock making 8.5:1 compression using inverted dome probe pistons. I plan on adding boost later about 10-12psi hence the lc setup, otherwise on n/a you want more compression because of the fact it makes more hp. remember though there is a limit that pump gas can take and too much compression will cause denotation, although aluminum heads help, too much compression will ping.