LS Valve weight VS spring pressure

[Warp Speed]

The pushrod needs to fit within the aloted space; sometimes a larger diameter pushrod is simply not feasible.

Plenty of room in even a stock ls for 3/8. Minor work for a 7/16.

A 3/8" diameter pushrod will not fit correctly through the head when using an O.E.M. L92/LS3 head, without enlarging the pushrod holes.
Trend and others make special 11/32" diameter pushrods just for that reason.
They worked fine when going to 8,600 RPM in my customer's application; some rubbing on the head can even help to stabilize the pushrod.

They didn't "work fine".........they worked! Lol

[Walter R. Malik]

Plenty of room in even a stock ls for 3/8. Minor work for a 7/16.

A 3/8" diameter pushrod will not fit correctly through the head when using an O.E.M. L92/LS3 head, without enlarging the pushrod holes.
Trend and others make special 11/32" diameter pushrods just for that reason.
They worked fine when going to 8,600 RPM in my customer's application; some rubbing on the head can even help to stabilize the pushrod.

They didn't "work fine".........they worked! Lol

OK ... they did the job they were supposed to do ... is all that mattered to him so, that is all that mattered to me.

With an 821 head a 3/8" pushrod could be forced in the hole with no free side movement at all. An aftermarket LS3 head may be different.
The intake pushrod with that O.E.M. geometry is slightly angled and not straight up & down.

[Warp Speed]

Hell, I've seen standard main bearings work on a .010 under crank too!

[turbo camino]

Schrodinger's 3/8" Pushrod...

[3pedals]

⅜ pushrods fit just fine in LS3 heads, not sure what all the fuss is about