bomax

iTrader: (3)

Awhile back I mis-shifted and broke and bent some of my pushrods. I also broke my lifter retaining bracket and thought I might have broken a lifter too, so I replaced it with another stock unit. However, I came to find out that the lifters in my 98 LS1 are a different style than the dealer currently sells. And at $40 a pop, I didn't want to replace them all on a hunch. The new one supersedes the old design, although it looked pretty much the same, it might have had slightly different weight, or something else internal to make it different from the other 15.

My question is, will it hurt performance to have 1 slightly different lifter? I doubted it at the time but I dynoed extremely poorly (30rwhp short) and I'm looking for reasons.

Anyway, fast forward to now I have a Procharger and heads and a new cam on the way. Since I will be opening the motor again, this question has come back up. Should I replace the lifters with Comp type R's? Keep as is? Put the old stocker back in and ditch the new one?

JF WS6

I'd go with the Comp R's if you're going to be running some beefy valve springs and cam. Might as well replace them with the motor apart. You're stockers probably have a decent amount of miles on them already as well.

bomax

iTrader: (3)

I should have been more specific. Although it's a 98, the car has only 30k miles on it, mostly highway. I am putting a baby cam in 218/224 .565/.585 116LSA. And the heads I'm getting are the Patriot 6.0Ls which come with the Crane dual valve springs. So I won't be running anything extreme. I'm hoping to just re use my stock lifters, but mostly concerned that the one different lifter might cause some sort of weight problem, or might even pump up at a slightly different rate.

JF WS6

I wonder what kind of spring pressure the crane duals have, because that's the real reason to go with Comp R lifters. Not to mention you're adding extra stress to components by running a boosted application, so the Comp R's still don't sound like a bad idea to me. I have Comp 987 double springs and they are almost too much spring pressure for the stock lifters which I still have. Personally I kind of wish I had replaced my stockers with the Comps when i had the heads off.

If it was me I'd just replace them for piece of mind, but if the only thing you're worried about is just the one new lifter being different I don't know that it would make much difference if any. I'm sure it isn't the reason you'd be missing 30HP.....

BLUEBYU

iTrader: (1)

Werd! What the **** was I thinking?

bomax

iTrader: (3)

I don't understand why you guys think you need them??

JF WS6

Because the stock lifters were not designed to be used with the high spring pressures a lot of these dual high performance springs have. Your cam isn't that aggressive, but if you use stiff double springs that have a lot of pressure it may be too much for a stock lifter to handle.

SMOKINV8

iTrader: (6)

Well.. I'm running GM lifters along with dual springs (and big lift), and it seems to be working out okay. What would symptoms be if the lifters weren't cutting it? Would you know, or would you be losing any power (due to losing lift)? Would it be more noisy?