rebuilding my 69 440. was previously rebuilt in the 80's (don't know details). had my heads shaved 0.012" and not the block. head gaskets are 0.04" thick now. with 9.31" pushrods i have about 0.06" of preload (cam on base circle of cam) on the hydraulic lifters (measured by marking the pushrod with w/out the rocker shafts torqued down to 25 ft/lbs). with the rocker shafts torqued down i can further depress the pushrod in the lifter by lifting the rocker tip and lifting rearward at least as much as the preload (>0.06"; tough to measure as both hands are in use doing this. plunger clearly has room to move past preloaded position).
rebuild is stock type....not a race motor.
i believe you shoot for 0.02" preload normally w/ hydraulic lifters, but how high can this go before needing to replace the pushrod with shorter length one's? i assume if i needed shorter one's would go for 9.27" (9.31-.06+.02 for preload). not looking to go out and buy custom or expensive adjustable one's, but don't want to mess up either.
looking around quickly to get one's a few hundredths shorter than stock means instead of $35 for a set it would be $100+. Are these really needed or can i just go with it as is?
thoughts?
Last edited by BTTG; 06/20/11 08:37 AM.
