No such thing as GS heads. They're just regular old 455 heads. The stage 1 head has the bigger valves. The heads you bought may have come from a GS but are the same exact head on an Electra or Rivy.
heads Yeah, but the 70 heads are nice for the smaller cc. 69 cc I think vs the later heads at 71cc or 78cc. You can have the stg valves installed, but the stage heads were 66cc in 70. - Bill :Comp:
Albert - Also keep in mind that you can't just have the larger Stage 1 valves installed without having anything else done!! In addition to the larger valves, Stage 1 heads had the bowls 'hogged' with a 77* cutter (I believe that's the right angle). Without opening up the throat, the heads would flow WORSE than the small valve heads. :Smarty:
okay guys what i eventually want to do is build a street motor w/ 450 hp, and i would like to have a 9:1 CR and a t 56 behind that. can i get a 9:2 CR with these heads.
Re: heads If one were to put '70 heads on a '72 engine what would it bring the compression to? When they lowered compression in '71 did they dish the pistons more? or use the larger cc heads? or both? I know the '72 cam isn't the same grind as in '70, how did that effect compression? I'm refering to the standard 455 here. Forgive me, I just asked alot of questions and perhaps I should have started a new thread, but I think they are relevent to Albert's question.
You can put a '70 head on any year block and raise the compression some. Due to the variances in deck and compression heights, the '70 wasn't a true 10.0:1 anyway. If I remember correctly, the rule of thumb is 1cc = .1 of a point in compression. Standard 455 heads are 69cc's uncut. Stage 1's are 66cc's uncut. The '71-'72 head is 71cc's uncut. But the '70s had a little better flow. You'd raise compression more but decking the block and milling the heads. The pistons are dished a good bit more. That's where the most compression is lost. In '70, I think the piston dish was like 20-21cc. In '71, it went to 28cc's.
