compression ratio ????

i have a friend with a 73 460 with d3ve heads and some speed pro cast pistons part#h582cp
was wondering what com ratio may be with them there a dish piston small dish from stock i know the heads are closed chamber and if he could find a set of c9 c8 or dov he could get more compression but thats what hes got thanks guys

You need to cc the heads and find the piston volume (stock cast heads can vary in cc quite a bit), you will also need deck height, bore size  and head gasket thickness when compressed. there are plenty of calculators on the net when you have these.  I like this one: 

http://www.kb-silvolite.com/calc.php?action=comp

I had a quick look at the pistons under that part number to do a guesstimate  but could not find the piston volume.

74f100 wrote:i have a friend with a 73 460 with d3ve heads and some speed pro cast pistons part#h582cp
was wondering what com ratio may be with them there a dish piston small dish from stock i know the heads are closed chamber and if he could find a set of c9 c8 or dov he could get more compression but thats what hes got  thanks guys

Assuming no other changes in the engine except overbore 0.030" and re-assemble, about 9:1.  Swap out the D3's for an early-style head and compression will increase to about 10.6:1.

Paul

P.S.: Assuming further engine "optimization" during the rebuild, the compression ratio could be as much as 0.50-0.75 higher.