Im debating on getting a set of 993 for my engine rebuild (350 +.03) but I dont know how much the 74cc chamber will bump up my CR. I want to still be able to use pump gas. I will be using flat top pistons (with 4 valve relief) what CR do you think I would get using these heads? Will this be alright with my cam... http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=100052&lvl=2&prt=5 ? What I mean is this wont raise my DCR too much for pump gas will it? Thanks

probebly 8.7-1

and those heads kinda suck... find something better...

ULTRA_KILL... I think your thinking backwards. The higher the head CC chamber size the lower your compression will be.

Same pistons.. 62 cc heads will have higher compression than 64 cc heads, 64 cc heads will have more compression than 72 cc heads, 72 cc more compression than 74 cc, etc etc

<font face="Arial,Verdana" size="2">Originally posted by night rider:
ULTRA_KILL... I think your thinking backwards. The higher the head CC chamber size the lower your compression will be.

Same pistons.. 62 cc heads will have higher compression than 64 cc heads, 64 cc heads will have more compression than 72 cc heads, 72 cc more compression than 74 cc, etc etc</font>

Oops, sorry for the confusion, I should have mentioned I was going from the 882 76cc.

8.7CR? Rats, was hoping to get 9 to 9.3. Im not sure what CR is safe with pump gas and iron heads since it varies with the cam. What chamber size could I get away with on pump gas and the cam I have? I was looking into a set of assembled 487 with enlarged valves (2.02 1.6) or a set of used S/R Torquer, but these two heads have about 75/76cc chambers. Could I have them milled while they are assembled? Thank you for your replies.

Use GMPPs .028" head gasket and it should be 9.1.
Also which SR Torquer did you find? Some are 67cc, 72cc or 76cc.

S/R Torquer are 76cc. I dont know which set of heads is better: 487 with enlarged valve, 487x, or the S/R Torquer. I cant seem to find any flow numbers for the 487.

Depending on which 993's you're talking about, they can flow better that the 487X head or even some aftermarket heads!
I have a set of GM Performance aftermarket 993 heads, that had some porting done to them, and they flow better than many of the aftermarket heads.

I'm running 426hp and 459ftlbs out of that motor.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33617&item=7970322141&rd=1

The SR Torquer should have the 2.02/1.6 valves, 3 angle valve job and good springs right out of the box, plus better chambers than old GM castings so if you have found a pair of used ones thats probably a better bet than those ebay ones unless those are cheaper priced.