I got the Yella Terra rockers for the LS1. I have 7.4 TR pushrods, TR224 Cam, TEA 5.3L Heads that are suppose to be milled to about 11.1 compression.

When I bolt up the rocker on #1 at TDC and check the preload I get about 2+ turns. Their instructions say to add shims to decrease the turns. Yet, it takes 3 shims to even get close.

So, would you say my pushrods are too short?

 

Doh! It needs a pedestal and shim and now I am closer to a good preload. I still may need to get different length pushrods.

My preload is about 1 1/4 turns before 22 ft lbs. What change in pushrod length would I need to change the preload to < 1 1/4 turns? Longer or shorter than my 7.4"?

 

To compensate for milling the head you need a shorter pushrod. To compensate for the smaller base circle of a high-lift cam you need a longer pushrod. Shorter pushrods are preferable to shims under the rocker stands. Your description leads me to think you need shorter pushrods. I think you should try 7.35 pushrods and eliminate the shims. And you should also get another opinion; just to be sure I’m not way confused. If Ron, Kimchee and Rice, replies, you can trust his recommendation. He really knows this stuff.

 

I've done several sets and in both instances used 7.350 p-rods - 3/4 -1 turn preload.

I beleive your 1 1/4 turns is still reasonable but wouldn't recommend more than that.

 

I just ordered 7.35 from Thunder Racing and a pushrod length checker in case 7.35 is not short enough. The shims are already on the car but I would say they are at least .05. So, if the 7.35 drops me 1/2 to 1 turn then I wonder if I take the shims out where will it put me. I expect .05 to a .1 change to get be below 3/4 turn.