if you are running cast iron heads, 10:1 is a bit strong, but can be done. cam selection will be important - you want to avoid detonation.

you want a fast car, but stock heads?? pick one or the other, you don't get both!

pistons come in cast, hypertectic (spelling not right on that) and forged. good, better best. go with hypertectic, stronger than cast by far, not as 'spensive as forged, and you shouldn't need forged.

auction..first heads, ARE NOT 68 heads ---the C6...number he posts are stands for 1966. these are 66 heads.

regarding the GT heads, go here and read this FIRST
http://www.ford-trucks.com/dcforum/DCForumID7/218.html

now yo need more information before you buy ANY heads...

also, any head made before 75 or so will have been designed for leaded gas - leaded gas is no longer available. one thing it did was lubricate valves seats, so without lead you need ot have the seats replaced - see you machine shop for info and costs. if you do not do this, you will regret it and be doing it again later - if you cannot afford to do it now, YOU CANNOT afford to do it TWICE!

Chris