When installing an after market set of heads (Dart Iron Eagle 308) and a set of roller rocker arms, how far do I screw the Polly locks down, keeping in mind the back lash adjustment (1/4 turn down after zero lash). I do not know how to work the rocker arm stud adjustment with the adjustable push rod to get the right geometry.

The way I understand it as you rotate the cam the sweep of the roller tip should be in the center of the valve stem.

I have set up rocker geometry more than a few times. It is difficult for me to explain just how to do it correctly. Maybe this link will help you out.

http://www.compcams.com/Technical/FAQ/FAQPushrods.asp

In order to sustain long periods of high rpm use the engine among other things must have the correct valve train geometry there was an article/build up in poker runs mag sometime back, also hot boat and power boat mag have done build ups on this critical subject. The posts above are good and should help u also ck hot-rod mag. good luck and take your time. J ps a lot of cam mfg. have descriptions on how to set the valve geometry, like Vinny posted.

The above precedures are how to adjust them If I am reading this right you need to set the Pushrod lenth.

I use a light gauge valve spring and I color the tip of the valve stem with a black marker then adjust the pushrod to get the
roller to smudge the marker as close to the center of the valve stem as possible when rotating the engine one complete
turn.

Now measure the pushrod and you have your lenth.
Then follow the correct lash adjustment.

Gerry

I have a set of addjustable push rods.What I need to know is where to set the rocker arm at the top middle or bottom of the rocker arm stud. Where to start, do I adjust them both up and down to get the rocker in the middle of the valve stem.

Here is a good link.
AS posted above.

http://www.compcams.com/Technical/FA...inGeometry.asp

Gerry- get out of here.....you are a kerosene burner now! just kidding brother!

Wheres the Love?

Sak aready said he would buy ya steaks if ya visited him
I say both of you guys come help me drive my tub.

I will buy the lobsters and Coronas!

Sorry dont mean to Hijack this Deal!

That's a deal! I'm Throttling ! Never ran a turbine boat before.....that would be very cool!!