I have yet another lt1 im working on and ive run into a little trouble.I have summit rollor rockers nsa and i test fit them without the guide plates. they fit good without them. however when i put the guide plates on then the rockers hit the screw in stud. what size pushrods should i run?

 

You mean the rocker is bottoming out on the stud???

Pushrod length should really be measured not calculated.

What are you doing? just replacing the rockers? New build? Maybe if you post some more description of the motor someone else will chime in with a suggestion. Stock block? Head gasket? milling?

-brent

 

Pretty much just another stock bottom end rebuild with a cc306. no milling or anything like that. GM headgasket,summit rr's, summit guideplates.

Yup. the rocker is bottoming out on the stud with the stock pushrods. Never had this problem before.Then again never used summit valvetrain before.

 

Before you go any further, are you sure the summit guideplates are the right spacing (distance between the valves) for an LT1? Its not SBC spacing.

-brent

 

Your definitly going to want to get an adjustable pushrod to find the right length. You want to make sure the rocker tip is centered on the valve stem through the entire valve motion. You mark the valve stem with magic marker and then cycle the valvetrain to make sure the sweeping pattern created by the rocker tip is centered on the valve stem.

-brent

 

were can i find an adjustable pushrod? When i ordered the guide plates on there web site it asked if it was an lt1 or gen 1 smallblock so i assume they are different. I of course bought lt1 guides.

 

Can you get adjustable pushrods from autozone?

 

You definitely don't need a different length pushrod. The things that will affect pushrod length are:
1- block deck height,
2- head milling,
3- lifter length,
4- camshaft base circle &
5- valve length.
You have not changed any of these, so the stock pushrods are ok, don't waste your time and money on checking the length. I had a decked block, and a small base circle cam, when I checked the geometry with a pushrod checker, it turned out that the perfect length was 7.200 (stock).
What you need is studs dedicated for guide plates, they have a shallow hex portion which should give you more clearance.
And I agree what was stated above bout the guidplate, ditch them for either the isky adjustable or the gmhp ones.

 

LT1 is different and its been widely known that the GMPP guideplates are the ONLY ones that will work properly. Also I got my pushrod length checker from Summit. The trickflow was the cheapest that I could find as were the Trickflow pushrods.