azgasser

I am looking to have a Comp Cam .581/.588, Duration - 224/227 at .050, and LSA - 114 degrees installed with the stock heads on my O3 Vette. This will flow through StainlessWorks long tube headers and high flow cats. I am planning on upgrading my springs due to the high lift of this cam. Should I look into changing the lifters with the new cam, since the original ones are mated to the stock cam? Also, should I change the push rods as well? Any HP guesses with this set up? I am making 335 RWHP before the cam. Thanks for all your great info and help

dug

iTrader: (10)

The only thing that has to be changed is springs. The lifters do not need to be changed because they are roller and dont wear on the cam like flat tappet lifters. Push rods should be upgraded to minimize deflection from the stiffer valve springs but isnt absolutely necessary. Since engine is a new, the oil pump and timing chain should be ok and not require changing. THe cam should be good for almost 400hp but closer to 385 because of the cats.

2001CamaroGuy

iTrader: (6)

As far as "wearing out" the stock lifters, that won't happen because they are roller tappets (even the cam won't really wear). Hydraulic cams and lifters come out of engines with 150K+ miles looking new. That said, depending on how many miles you have on the stock lifters, you might want to change them just as a preventative measure against the hydraulic internals being worn and not operating correctly with the higher ramp rates and spring pressure. I personally reused my stock lifters (had 20K miles on them) and now wish I had used Comp Rs as I am limited on how much spring pressure I can run on them (getting valve float but can’t increase spring pressure till I replace the lifters).

What springs are you going with? If it’s the 918s then you are within the limits of the stock lifters (spring pressure wise).

You really should change the stock pushrods out as they are pretty soft and tend to flex even on stock valve trains. When they are subjected to faster ramp rates and high spring pressures, they really take a beating. If I'm right, the stock pushrods are 7.380" long vs. the aftermarket lengths are in 0.050" intervals (i.e. 7.350" and 7.400"). Usually people just run a 7.400" pushrod as aftermarket cams have a 0.030" smaller base circle and you need the longer pushrod to make up for that difference in valve train geometry.

NiceTry

iTrader: (1)

lol for sure put new pushrods

BlackWS602

You just need valvesprings.

You don't need pushrods, no harm will come by not running hardened pushrods.

Alot of the hardened pushrods refer to the outer coating process the rod goes through so that it can be used with guide plates.

silverTA

u need pushrod

TransAm00

i disagree with pushrods. I kept my stock ones and have had no trouble. I would rather break a few pushrods than have stiff ones and something else go boom bitch. just my 2 cents