Measuring Pushrod Length

[S10JUSTIN]

Hopefully this post isn't confusing to read, I am just learning how to do all this stuff so here it goes. I'm rebuilding a 95 Camaro 3.4 right now and I'm trying to figure out what length pushrod I need. I have read this post about how to do measure the length, and it says is to tighten down the rocker arm and then measure. Wouldn't this mean that after measuring the length and then adding the .050" that you wouldn't have room to adjust the valve lash. According to the 3.4 gen I specification sheet on the forum it says to turn the rocker arm bolt down 1.5 turns after zero lash but the Haynes manual I have only says to give it 3/4 of a turn after zero lash which is also confusing. Also, if you don't have to worry about adjusting the valve lash and you do just tighten down the rocker arm, I haven't seen anywhere mention what the torque spec for this would be.

[Frank Reiner]

As a general matter the iron heads will have a rocker arm setup like the small block V8s, and as a consequence the rockers are adjustable.
If the base circle of the cams is significantly smaller than the production ones a longer pushrod may be required. Otherwise, with hydraulic lifters, 3/4 of a turn preload after zero clearance will suffice.

[SappySE107]

To do adjustable rockers, you have to check that the rocker arm sweeps across the center of the valve tip. That would be the reason to change pushrod lengths with an aftermarket cam. The .050 is the last, so you would be putting that into the pushrod for non adjustable rocker arms.

Alldata calls for 0 lash plus 1 turn. The rocker arm nut thread pitch is what actually determines the number of turns. Whatever it takes for .050".