Comp Cam extreme energy 490,
Hydraulic lifters, non-adjustable rockers, and the heads were milled .004. He put in a stock gasket, and stock-sized push rods, so the only difference is the .004 milled. So, we should be pretty darn close aye?
There is still some fudge factor considering not all aftermarket "stock" replacement components are identical to oe spec. But if you just put the factory pushrods back in..then u r prob close....but close is for horseshoes and hand grenades...not engines.
1. with rockers loose, Rotate engine until lifter is on back side of cam lobe.
2. Slowly tighten rocker shaft until zero slop remains in the pushrod. (All 5 bolts)
3. When you reach zero lash (no more slop) on the pushrod. You should still be able to tighten the rocker arm bolts a "little" this would be your "pre load"
4. With a flashlight...you should be able to look and see how many threads are left on the rocker arm bolts when u hit zero lash.
This is the horseshoe/grenade method to see if u are even close. It wont be perfect bc the bolt "turns" wont be 1 for 1 to pushrod length due to geometry. ..but should tell u if the p-rods are so short..that u cant get zero lash....or soo long that u are opening the valve.
Or...spend the $20 and get a length checker and do it the right way.