i am in a pickle here, hope somebody knows for sure though. i have the k 413 ram. i have the 516 heads i cleaned up a little bit ( gasket match, clean around inside runner at valve ) in place of teh stock heads of comparable size chambers and valves 520. they are 74 cc heads. the 516 heads have the bigger valves , ( cant do a stock rebuild, not me.) so teh problem is am i going to get teh gains desktop dyno promises of apx 60 hp and 30 something tq. rom bolting the heads to a stock ram - cammed higher lift ( maybe .470 or something ) as opposed to the " i caling stock 516 heads"???? i am replacing the 413 engine with a 440, but have to wait a while longer if i am to get the edelbrock heads. i cant switch heads later because you supposed to go up in compression with alum heads, but that is not the case. stock is 73, and smallest edelbrock is 84. thats apx 1 pt in comp lossed. not gonna happen in my car. so do i wait to get the edel heads and leave teh car on the trailer or use my 516 heads and pray somebody will write back with true dyno experience that teh gain isnt anywhere near that because we only run upto 5500 rpm or so. HELP!!!!!!!!!!!!! sorry so long, sorry to bother, tim ps, stock k cam ( thank you all for helping with duration ) and 9.5 with 516 head comp, 10.25 alum heads if it matters to anyone [Non-text portions of this message have been removed]