So heres my deal. Ive been out the game for a few months due to an ls7 lifter in my z deciding to puke its bearings. The lifter was jammed in the bore and I finally got it out with no harm done to the motor ( knock on wood). However now I am scared maybe my pushrod length is incorrect and I do not wanna have to fix it again.

My setup is TSP stage 2.5 5.3 heads milled to 59cc, TSP 224R 224/224-581/581 112lsa, GM MLS head gaskets, Stock rockers, LS7 lifters and 7.40 cromoly pushrods. I know I need to measure with a checker but I have never measured them before and am lost. What has me worried is that I was recently told that the LS7 lifter cups sit .05" higher than the original ls1 lifters which woud mean I need 7.35 length rods? I am sure someone else on this board has this setup and can chime in to assure me my Pushrod length is either correct or not. I need help on this bad guys, I dont want to have to pull these heads again!!!! Working on this thing is getting old!!!!

 

I've done some research on this and it seems most guys have to go with a shorter pushrod when they install LS7 lifters.

 

thats what Ive been reading as well but it seems some say shorter and some say 7.40's are fine, Im confused.

 

The best thing to do is to get a checker and measure. Then add in the pre load that you want. Search for posts by vettenuts, he knows his stuff.

 

7.400 wer way too long and you had way too much preload which collapse your lifter.
MEASURE that is the bottom line. It is not hard, actualy it is monkey simple

 

Here is how I do it: Link

Note, if you are buying Manton pushrods the procedure will be slightly different as he uses overall lenght, not gauge length.

 

Vettenuts thanks for the write up, It cleared up my confusion. Thanks

 

Make sure you change your plastic lifter trays. One cost me 3 motor builds.

 

new ls2 ones are already installed. I made sure to do that

 

Im running a setup pretty dang close to yours minus the stage 2 heads part, im using stock heads, and my push rod length to use was 7.4 with LS7 lifters. Im going to keep close eye on this to see how it turns out.

 

It might be a while, I just heard comp has the length checker on back order till the end of the month!!!!

 

I measured mine out and with my comp cam and came up with a 7.36 measurement with the .060 preload added in. I just installed 7.375 pushrods since i got a deal on them and they seem to sound fine so far.

 

The OP's heads are milled so his PR's need to be shorter than yours to begin with.

Good luck OP on getting your checker soon.

 

What's up with the trays? Would a 36k mile car need them?

 

I really wouldnt worry about your lifter trays with that low mileage. I had 73k on my car when i pulled the heads and mine were fine. I just replaced mine because I was in there.

 

For $20, I swap them every time. If you ever need to pull the cam the newer the trays the better they hold the lifters.

 

So one more question. Would having too long of a pushrod cause valve trainoise? Mine is the prominent very slight tick at idle aka sewing machine noise. thanks guys

 

It sure will. to much preload will make alot of noise. from what i have read on here the LS7 lifters sound good at .060 preload. Im currently running mine at.075 and their a little bit noisey but not to bad.

 

Boy. If I spent $20 on everything I really needed but really didn't I would be really broke LOL. I plan on using the 5/16" dowels regardless anytime I do the cam so the lifters don't drop. Guess I will put the $20 towards some new skins.

 

yeah well cheap insurance with 73k miles on the motor.