Jim85IROC

yeah, I know, measure. I did, but my measured values don't jive with what I expected, hence this post.

My motor has bone stock LS3 heads, with GM LS3 head gaskets, mounted to an LQ9 block at standard deck height. The cam is a 227/231 Comp grind.

Most of my reading indicates that cams with above a 224 duration are ground on a .060" smaller base circle, which would indicate that the "right" pushrod length would be 7.430 as opposed to the stock 7.4. However, my measurements indicate that I need a 7.35" pushrod in order to have ~.050" preload. I expected to need a longer than stock pushrod, not shorter. I measured all 16, with a low measured at 7.3" at zero preload, a high measured at 7.3125, with most right in the middle at 7.30625. Add .050 preload to that, you get 7.35625, which tells me I need 7.35" pushrods.

But again, does it make sense? I expected to need something longer than 7.4, not smaller.

I'm ready to pull the trigger on a new set of Trend pushrods, but before I waste a pile of cash, I want to have confidence that my numbers are right.

carlrx7

stock length is a lil bit smaller than the 7.4 rods. bout 7.385

you should have more preload than .050 . shoot for around .080" preload.

i'd use 7.4" pushrods, how did you measure?

Jim85IROC

I don't want too much preload. .050 is more to my liking. After talking with Al at Manton, he agreed that even if it's a little noisy, it's better to have a little less preload.

I measured with a Comp adjustable pushrod length tool. I measured 7.300 at zero preload.