Pushrod Valve Contact Pattern
 

Hey Everybody and happy Easter!

What do you think of this pattern and length of pushrod for a mild solid roller with 263 @ .050 and .631 lift with 1.5 rockers?

Sorry sideways view.

Sorry SAME valve SIDEWAYS

Another valve

Sideways again.

The sweep is oriented towards the outside or end of the valve away from the intake.

Wondered if a pushrod .050 shorter would center the pattern better?

I think that looks pretty good. I was told by my machinist you want it past center like that. That's how I've done my 455 and the latest 400 I did.

Looks decent. Some say at half lift it should be in the center of the valve

Would be content with that as is

I was told by a head guy that if the pattern is off center a bit, you want that offset to be on the intake side, not the exhaust manifold side. Hope that makes sense. There is a great video on here about push-rod pattern.
https://www.youtube.com/watch?v=o5is9BsH5OU

This is what you are looking for. If it's offset like Chuck's post describes and you're not looking to buy another set of pushrods I think you'd be fine with what you have.

The offset is toward the exhaust.

I wonder if a .050 longer or shorter would center more towards the intake side.
Also, could it narrow the Sweep?

Thanks

Get an adjustable pushrod from Summit. They're pretty cheap at around $20.. Then you can mess around with differing lengths and get your pattern centered and narrowed to your satisfaction

If it's offset toward the exhaust, would lash caps help bring it back to center? It looks pretty close to me.

What rocker arms are involved here?
They are not all the same geometry despite being called Pontiac

I have a set of Comp ultra gold high end rockers that fit like socks on a rooster, I set them on the shelf and bought Harlan's that fit perfect, old school E'heads original valves

I put those Comps on a #13 iron head with a RA-IV valves = much better fit with the valve tip closer to the stud

1.5 Harland Sharps e head

The pattern should start on the intake side

I used the Straub 1/2 lift method. It resulted in almost a 3/8 inch longer pushrod. It narrowed the trace considerably, but also moved the trace considerably towards the exhaust.

I second this. I've run mine that way with no problems.

GT