New valve train noise
 

I recently changed the head gaskets and everything went smoothly. Only problem is now I have lots of valvetrain noise (I think) when it's warm. Doing some searching revealed that the rocker arm shafts have some lash that can make this noise. Is there a way to measure this without pulling the head?
Do you think I could adjust the pushrods when warm and quiet this thing down? Any other suggestions?

If the noise started after the head gasket change, my first go to would be to take a look at the pushrod adjustment. Rocker lash requires removal of the rocker boxes which means taking off the heads again. That shouldn't have changed any after the new head gaskets unless you took them apart and mixed up the spacers.

You're right, Professor. I've been studying the pushrod adjustment procedure and I think I've got it but I'll try again tonight.

IMO - If you didnt have noisy valvetrain before and you reinstalled same parts you shouldnt have now. Rocker shaft end play shouldn't change with new head gaskets. If you really wanna check you only need to remove the rocker boxes not the heads to check because rocker boxes sit on top of the head. I believe you have a pushrod adjustment problem.

Pushrod adjustment simply centers the lash in the center of the oil filled lifter assembly. The goal is to adjust to zero lash and then make pushrod longer to get in the center of the lifter operating zone. There are 2 ways to do this, the dry method requires the lifters to be dry and you simply keep extending the pushrod until the lifter is fully compressed then you shorten the pushrod the prescribed number of turns to center the lifter assembly in the oil cushion zone. Once the lifter has been pumped full of oil you should use the wet method which requires you to extend pushrod just to the point the pushrod touches the lifter and you cannot move the pushrod up or down (Zero Lash on the yet to be compressed lifter). Then extend the pushrod the prescribed number of flats on the adjuster and lock down. Most important - Wait 15 minutes after each pushrod adjustment to allow oil trapped in the lifter assembly to bleed down before cranking engine to next position. (Oiled lifter was fully extended and you just adjusted to the middle of the lifter zone which because the oil is still in there will open the valve too far until it bleeds down).

Aftermarket pushrods have varied threads per inch and usually come with the prescribed number of flats based on their threads per inch. If you are using aftermarket be sure you understand what you have. If using stock pushrods follow the manual for number of flats or total turns.

A few things:
1. Do you have solid or hydraulic lifters? A lot could have changed in 40 years.
2. Best to adjust each valve when the same valve on the other cylinder is at maximum lift. i.e. adjust front intake when rear intake is at maximum lift. If you have a kick starter, this is very easy to do with the plugs out, if not 4th gear and rotate the back wheel.
3. You can't get the rockers off their studs with the heads in the frame. As noted above, unlikely the rocker end play got worse overnight.

He could have wavy washers installed when they crack the washer they become noisy

from the push rod loose and having up and down play - turn it down to zero no up or down movement and adjust 3 full turns - as joe has instructed you to do with location of the lifters

try that before you start removing heads

This is great information, thank you! My first shovelhead and the learning curve is steeeeep
The lifters are hydraulic. I pulled them and cleaned them when i had it apart.
When I adjusted the pushrods however, i did not use the 3 full turn method. 3 full turns extended? I think I did 1.5.

Yes, and the broken pieces won't do the motor any good. Hope it's not that.