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Discussion Starter · #1 ·
Ok I have a 95 formula that I purchased that has a cam and maybe lifters of an unknown orgin. Thing is the cam has an extremely large lope to it. It shakes the car violently and is almost un usable in parking lots. Being that I have no way to find out what cam is in the car and it's my daily driver I'm opting to go back to stock and hope for the best. I've also identified what apeares to be a lifter or 2 causing rocker tick. While I'm in the motor I wanted to replace the lifters just for insurance. I've read ALOT about the Ls7 lifters being "the " replacement for the Lt1's. yet everyone says they have needed custom length pushrods. I don't have the luxury of downtime of more than a day ....... So I need a tried and true drop in replacement that will work and is reliable. Please help if you can. I don't want my baby to suffer because of the previous previous owners possable stupidity.
 

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LS7 lifters don't require a new length pushrod.

Is it the absolute "right" way? No, but a hydraulic lifter will be pretty forgiving on the tiny difference in height between LT1 and LS7.
are you sure about that? i have a set of dead LS7 lifters laying next to a set of dead LT1 lifters, and the difference is visible.

the difference in lifter height isnt something that the lifter will just 'soak up. your rocker angle is going to change for sure

i sure wouldn't be messing with that kind of geometry difference on a big cam. maybe on a small one. the effect of poor valvetrain geometry is more damaging the higher your lift is.

GMPP makes a nice lifter kit if you want stock geometry.. pn# 12371042, affordable and comes with guides.
 

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FWIW I think that that kit you posted steveo probably comes with the ACDelco ls7s to be honest. On Jegs when you type in the ls7 lifter part number it comes up with Chevy performance lifters but they are ACDelco ls7s.

With a stock engine it probably wouldn't matter. I mean they are "stock replacement" now directly from GM aren't they? Either way, it is always a good idea to check the rocker sweep on the valve stem tip when changing anything that could affect valvetrain geometry for peace of mind, especially being that the OP has an aftermarket cam and hopefully valve springs with it.

By the way, to the OP, I'm slightly curious as to what you mean exactly by violently shaking and with almost unusable in parking lots?
 

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Discussion Starter · #5 ·
Well a long day of working with her and I feel almost stupid........ I will say I'm new to the LT1 platform so please don't tar and feather me for being an idiot. I finally found the fuel pressure regulator and went to check to see if it was bad. What I found was the vacume line had been chewed in half by a mouse. It was hidden on the back of the intake so it wasn't visible.

What I was referring to as almost unusable in parking lots and violent shaking was just that..... It idled so poorly in drive or reverse at parking lot speeds the whole car shook as if it was a top fuel dragster, but at the same time tried to die. I'm going to say again I'm an idiot........ A vacume leak combined with a cam seems to be the perfect combo for just that. Fixed the line and shes not so bad anymore. Haven't got to drive her much yet but she's already doing better in reverse and drive just going up and down my driveway. Now lets see if a properly operating FPR will net me better fuel milage......
 

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Discussion Starter · #6 ·
FormulaJoe....... From what I can tell the valve train is stock. I did check for coil bind and luckily there is still gaps between the coils of the valve springs. Being the previous previous owner did the work I'm leaning towards it being stock lifters and pushrods too. I'm going to pull the intake and change the lifters...... I'm just not sure for what though.
 

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before you change the cam, you might just put a stall in ( im assuming its auto) im pretty sure thats whats giving you a "dragster feeling"
 

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Discussion Starter · #8 ·
It's settled down a bit since I fixed the vacuum leak.
 

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lol thats priceless i probaly would of thought something was wrong to if im honest lol, anywho i am wondering the same thing, finally budgeted headers, rims, tires, rear suspension and have it all done in a certain time frame but im starting to hear some top end chatter, so now imma rework the budget :) lucky me
 

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Discussion Starter · #10 ·
I'm going back to stock cam, a good set of lifters, and a stock ECM. Only way I can be sure of what's been done to the car. Valve train is stock except cam..... It's aftermarket and I have no clue what it is.
 

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You can check the duration of the cam as well as the lift without pulling the cam. All it takes is a dial indicator, a degree wheel and some pumped up lifters.
 

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Ls6 or 7s cant remember, one of the two. Work great with my .610 lift cam and stock pushrod and i take my motor to 6800 all the time
 
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