What is the recommended lifter pre-load for the GENIII engines? In other words, if you were putting an engine together with new lifters and using a pushrod length checker, and you turned the tip of the checker up until there was 0 lash, how much longer of a push rod would you want than the reading on the pushrod length checker?

 

We like to see .040"-.080" of preload. Shoot for .060" in the middle.

Happy modding!

Richard

 

I'm running .035 lifter preload with my combo. With the 7.4 pushrods it was at .125 lifter preload. Tons quiter now and runs smoother

 

You are the exact guys who I hoped would reply in this thread, thanks Richard and Joe I don't even have my trans fixed yet, but I'm already planning on putting my LQ9 together within the next year or two. Getting closer...

 

When you get close to buttoning the motor up, you should always order your pushrods last. Get a pushrod measuring tool and measure your preload. There is roughly a .050 difference in lifter cup depth in the old style lifters vs. the new ones. It's beyond me why sponsors keep pimping out the 7.4's unless that's what you really need. My heads with only .007 milled, stock gasket and LQ4 shortblock running LS7 lifters needed a way shorter than stock pushrod.

LS7 lifter on the left in both pictures........

 

Wow, thanks for the pics Joe, I can see the difference Yea, I planned on getting the pr's last, already have a Comp pushrod length checker...it was like 12 bucks when I bought it. I'll be getting my heads milled around .030 so I'll definitely need a shorter than stock pushrod

 

I found the exact opposite, but Im running stock truck lifters.

 

What year lifters are you running stock48? The new design lifters weren't released until 05. So yes I could see if you were running the old style lifters with a 7.4 pushrod, stock heads you would probably be better off with the 7.4's than the 7.350's.

 

 

Im running the older style lifters. With my .566'', 155/335 LBS spring PSI and ~.100'' preload there almost dead quiet. My old setup with .030'' preload less lift and spring, same style lifters was obnoxious. I have some 7.320' s but didn't like the geometry with them.