How are you coming up with those numbers?

Choose a target preload and then measure with your tool. Then order correct length rods.

 

7.375 should work but measure to be safe

 

Also since heads are milled it's more guessing.

I'm running 7.325 rods

 

Those aren't exact numbers just basically stating those to make sure I understands it correctly. I plan on getting in there measuring the length with my length checker and so I get the checker and get it set to where the rocker has zero lash and then add e .075 lifter preload to that number to get the correct pushrod length?

 

correct

 

Always measure for proper preload. Ls7 lifters bottom out at .130" to .150 preload, I measured it. Typical preload is .075 for stree tmotors. Base circle of cam affects pushrod length. If your cam has stock base circle you should need shorter because you milled heads. If small BC, you'll need stock length to longer pushrods. Cams typically use small base circles starting at 600 lift. Read up on valvetrain geometry basics.

 

Hey guys, first time poster here (long time reader) lol. thought id ask a question since this thread is already on the topic.. I had a lifter go in my turbo 5.3 last week while doing a good pull down the highway so i did the ls7 lifters new mls gaskets and a set of arp head studs since i was in there this weekend, then i measured for pushrod length and threw a set of comp 3.50 (down from my 7.4) rods in there wich puts me at .050 preload. Now when its running it sounds much more sewing machine with the od tick tick in between like it was doing before just not as steady.. Any idea what I could do or check to see why its doing this new issue? I also pulled rocker by rocker and fired the engine up prior to replacing the lifters to make sure that was it and once i got to #8 intake the sound was gone so that showed me it was the lifter which is when i went ahead and changed them. now i did the same test to see if all the sound was still from that source and the noise is unchanged. so its coming from somewhere else now. Oil pressure is good, flex plate isn't cracked, torque converter bolts are tight. I don't know what else to look for..

 

Alrighty just a follow up here! I went ahead and pulled each rocker and did a quick fire up for each until I found the ticky lifter. It ended up being #7 intake this time. These are brand new GM ls7 lifters so I must have got a faulty one from the factory so ill be changin er out this weekend coming!

 

How about NO! Stop spreading bad information.

This is correct....and the reason I recommend 7.425 when someone swaps to an aftermarket cam if they wish to maintain stock preload. Aftermarket cams are typically .050 smaller in diameter, split the difference because you are only concerned with distance from center and you can see why I recommend that.