the heads are GM castings with 2.02intakes .They are 76cc. I don't have the casting #s handy but I pretty sure they start with 4. The valve springs are double wrap 1.47 diameter . I have checked the spring pressure with a frends moroso checker. It takes 110 lb to open valve off its seat and fuuly open it takes 300 lb . The cam it just ate was a Comp Cams Extreme energy . Advertised duration is 274 in./286 ex. and at .050 in. is 230/ex. is 236. Lift with 1.6 rockers .517 in./.520 ex.The cam I have now is one step down. advertised duration 268 in./280 ex. at .050 it is 224 in./230 ex. Lift is .507 in./.510 ex. with the 1.6 rockers. The rockers are the stamped steel kind that I got from P.A.W.
[ June 07, 2002: Message edited by: eblyon ]</p>