dankhts

Changing heads/cam etc in my '02 LS1, heard that I should use LS7 lifters and lfter trays, and that they're a direct replacement .. any good/bad reviews? Any better lifters to use, or should I just replace them with stock lifters...
Thanks in advance

geezel

LS7 Lifters are now the stock replacement for LS1's. There are better / pricier lifters out there but most feel the LS7's are adequate. New trays are cheap - best to buy a set.

SteveDoten

LS12367, all the same

newer trays ID's by indent for block

www.gmpartshouse.com about $150 or so new for lifters IIRC

fst85vtt

keep im mind the ls7 lifters plunger is .050 higher than the old ls1 lifters to keep the same preload you had you will have to run .050 shorter pushrod

0HinsonSuperCars

The LS7 Lifters will work just fine. We keep them in stock.

GM LS7 Lifters $145

Seth

SteveDoten

news to me; GM is not supplying the info in the new parts

lucky131969

First I've heard of this...where did you read about this?

fst85vtt

Yeah i just learned it a few weeks ago.. take a ls1 lifter and campare side by side .. with a 7.4 pushrad i had .110 preload there is a write up on ls1 tech compared the two and measured plunger height.. I do realize that everyone has a opinion on preload some say its fine to run .100 or more. I used 7.4 7.350 and eneded up using a 7.325 and now have a very quite valvetrain

lucky131969

Wow....think of how many LS1/6 engines are already out there with LS7 lifters, and 7.4 push rods.....most vendors I've seen(including GM) suggest the LS7 lifter is a direct replacement for a LS engines. So are the all misinformed, hiding something, or just wrong?

fst85vtt

well i guess it depends on how much lifter preload you are comfortable with.. ive seen guys saying .100 is recomended.. Thats what i would have had if my heads werent milled... I just couldnt live with the noise.. so that being said most stock head guys would be ok with a 7.4 pushrod but my car was noisy until i installed the 7.325 giving me .032 preload

zeevette

Jeez, I've got 7.9" PRs. I wonder how come it's so quiet with the Caddie racing lifters?

lucky131969

Ok, I'm a little slow...so bear with me. Your heads were milled, so wouldn't you have had to use a push rod checker to verify the correct length? This sounds like the shorter push rod length requirement was precipitated by the head milling, not the LS7 lifters.

What am I missing?

vettenuts

I have read this as well. However, you would think there would be a bulletin on the need for different pushrods. However, there wasn't a bulletin on the cam plate that now requires special bolts and a lower torque value as well so who knows. That's why I always advocate measuring but most want the know the length without using an adjustable pushrod to figure it out.

MVP'S ZO6

do you need to replace the trays and the push rods need to be shorter? I'm already running (or going to be running) shorter pushrods because of my cam. does this thread suggest that I may need an even shorter push rod to make up for the plunger in the LS7 lifters? Just FYI cam specs are .595 lift on the intake and exhaust side, 234 duration on the intake side and 242 on the exhaust side. with a 114 LSA.

fst85vtt

Lucky my heads were only milled .006 just a clean-up i installed the 7.4 per the place i bought the cam( didnt measure) I only became concerned when my valvetrain got the notorious lifter tick..
I actually was thinkink loud valvetrain= not enough preload, I was wrong.. I contacted alot of places trying to get recomended preload for the ls7s and heard everything from .030-.120 many people are running 7.4 pushrods and havent had problems but also on that note many people are running 7.4s and never checked for correct length and complain about valvetrain noise.. Did you check the wright-up on ls1tech the comparison of the ls1 -ls7 I couldnt find it.. as noted befor my car didnt quite down till i went with the 7.325 and i am also running a stock mls gasket so that isnt an issue

1bAD I guess the jist of it is you have to measure lol what i was getting at is that you will be hard pressed to get an exact preload requirement for the ls7 Im just saying what worked for me,,, Hope this helped

MVP'S ZO6

Roger that, Trial and error it is.

Y2Kvert4me

Trial and error it should not be, that was his point.

Measure first, buy exactly what you need second.


FWIW, compared to stock, your aftermarket cam will need longer pushrods, not shorter ones. Any other changes to the head/valvetrain setup can alter pushrod length...the smaller cam base circle is only one variable.

fst85vtt

Thanks y2k thats what I was getting at its hard to measure for what you need if you dont know what preload your trying to achieve I was having a hard time calculating my numbers because things werent adding up to what they should be thats when i found that the ls7 plunger was higher than the ls1

MVP'S ZO6

yup hard to add A and B if you dont know what B is.