Rob94hawk

iTrader: (1)

This is cylinder #1 intake valve and the mark is leaning toward the exhaust valve. I remember reading that as long as it's toward the exhaust it's ok. Correct? (Note that this is with the test pushrod @ 7.2", I never took pics of the correct rod length and they all made this mark.) Thanx

wrd1972

iTrader: (12)

It looks decent. I will speculate that if you put in a 7.150" PR, the pattern will move to the center but the sweep will get larger. More sweep means more parasitic power loss and IMO has more negative impact than the patter being a tad off center as shown in the pic. You definitely dont want the pattern going much further to the exhaust side than what is in the pic.

wrd1972

iTrader: (12)

It looks decent. I will speculate that if you put in a 7.150" PR, the pattern will move to the center but the sweep will get larger. More sweep means more parasitic power loss and IMO has more negative impact than the patter being a tad off center as shown in the pic. You definitely dont want the pattern going much further to the exhaust side than what is in the pic. BTW it is near impossible to have very minimal sweep and the perfect centered pattern so avoid looking for that treasure.

Rob94hawk

iTrader: (1)

So your thinking is to stay with the 7.2"? Haven't ordered the PR's yet so I've got time to think things through.

spudnick3119

If you have a pushrod checker tool, then test one with 7.15". Are you using LS7 lifters? They tend to require a slightly shorter pushrod. I ended up with 7.15" pushrods with stock, untouched heads (not that you should go by that, always measure).

Rob94hawk

iTrader: (1)

I have new LS7 lifters and with the PR checker the mark was centered but off to the exhaust side.

Interesting that your PR length is the same as mine. My heads are milled .012" and the head gasket is .026". What gasket and rockers did you use?

RamAir95TA

iTrader: (2)

Are your guideplates centered on the rocker studs?

Rob94hawk

iTrader: (1)

Yeah. That was a PITA. I eyeballed them, hand tightened, then incremently torqued them down.

Big Al

iTrader: (1)

I ended up with 7.1's. This is something you need to check yourself. Multiple valve jobs or aftermarket valves will change it.

Al 95 Z28 w/ Manley Pro-Flows

gregrob

iTrader: (8)

That is an internet myth. The cup height is exactly the same...

If you required a shorter pushrod it was not because of that.

spudnick3119

There were pics posted a while ago on cz28.com showing the cup height difference between stock LT1 and LS7 lifters, maybe they changed... that's why I said to measure and be sure.

wrd1972

iTrader: (12)

I measured the two side by side with a dial indicator a while ago. The cup in the LS7 lifter sits about .050" deeper in the lifter body. IMO, they did this to the cup end to provide more metal above the retainer clip to for a bit more strength.

Regardless, this slight difference will do little to affect PR length.

Rob94hawk

iTrader: (1)

Talked to a Comp cams rep. He wants me to do it again.

the_merv

iTrader: (88)

.050" of an inch is a decent amount on the Pushrod geometry..that's a .050" longer Pushrod needed to compensate for it.

My question is what exactly was the Lifter you had?

I ask cause my LS7's were shallower than a stock LS1 Lifter..and I have a stock set of Lifters here in my garage that came out of an LS1. They arent stock LS1 Lifters..they look identical to LS7 Lifters, but the cup is the same as a LS1 Lifter.

Here is some info I found to help out FWIW..

LS7 on the left, stock on the right.



http://www.camaroz28.com/forums/showthread.php?t=690137

the_merv

iTrader: (88)

Here's another one to help..

https://ls1tech.com/forums/15011466-post7.html

BALLSS

as suggested I would use the adj PR tool at 7.150 and 7.100 and pick the one with best pattern.

looks like you could go slightly shorter on PR

wrd1972

iTrader: (12)

I had my original 95 LT1 lifters and a newer set of LS7's bought in 2007 IIRC. Looking at your pic, that metal lip above the clip that captures the clip, on the LT1 lifter that lip was thinner and on the LS7 lifter it was noticably thicker I assume for additional strength. I also dismantled both and cam to the conclusion that the guts of both were identical. From what I saw, the cups appeared to be the same and the depth at which the PR sat, also appeared to be the same. It was the depth the cup sat in the body (bore), due to the moving of the clip, that appeared different to me.

SS RRR

iTrader: (2)

Absolutely. This was the problem with the Comp R lifter. The later versions had a paper thin retainer clip. Those with unstable valve trains would toss a lifter, the plunger would then hammer on the clip, the clip would effortlessly break and then you would read about the bitching of the lifter being bad. That clip serves no function while the lifter is in the engine and the valvetrain is properly adjusted.

wrd1972

iTrader: (12)

the_merv

iTrader: (88)

Agreed. I guess the height difference has to be accounted for with the Preload.