were those springs shimmed? fixed a bent valve/broken guide for a fellow member with kibblewhites, those springs shimmed over .100. about the only thing that will break a spring is coil bind, and all 8? 30 yrs building engines, installing up to 520 lift cams,never seen anything like that. sounds like some extreme seat pressure to wear out cam and break springs. u also need to ck int. seats valve seal from hammering by valve. stk. springs ok with 08 race int. dont like carpenter springs, lose too much tension quickly. ape may be good alternative. as far as losing power from spring pressure, springs store energy used to compress, returns same amount on valve closing side. lobe/ bucket friction increased though. decking will provide more power, good cnc vj will do same increasing flow and ex. porting will definatley make a difference. often overlooked and a mistake to do so, everyone says ten head factory ported, not on ex. it's not. sorry for the problems u had, but now is a good time to make several more hp with decking, vj, and ex. porting. have a good builder for vj and deck. lmk if u need any help with ex. porting, done a few. pic's under profile. good luck on repairs/upgrades.
Last edited by gazx10; 05-01-2013 at 11:04 AM.