I checked some threads, but didn't find the exact info needed. I have a 79 block, .030, with .012 cc recessed pistons, all together. Cam is Lunati barebones cam (.214/.224 @.050, .472/.496 lift), and matching springs (~115 lbs closed?), 1.7x roller rockers, 8.15" hardened pushrods, hosed up my 70W heads and saw some new/bare/iron GT40P's for $200 on eBay. Any idea if my valve springs and pushrods could be used? Where to pick up the valves, and what lengths should they be for 351W setup? Any assistance would be great. Those exhaust ports look so much wider, and the guy selling the heads stated the intake flow would be around 200cc / 145cc intake & exhaust at .500 lift. Any smog shiite to worry about with them? BTW, I read GT40's are better than GT40P's but what are the benefits? Also see GT40 aluminum heads on eBay for around $550 (per head-false advertising f'er) with valves and springs. Should I just go that route? Realize I'd need to take these head types to a machine shop to accommodate 1/2" head bolts. Also, forgot to mention that I have the performer dual-plane Edlebrock manifold, and 600 cfm Edelbrock carb, or a 980 cfm Holley. Eric.