Pushrod oiling/heat?

That’s not good.

Do you just have the stock rocker oiling?
No restrictions anywhere?

Here’s a test......
run the priming tool, slowly rotate the motor until the holes in the cam line up with the holes in the cam bearing...... so you’re at the point of maximum oil flow to the top end on one side.
See how far away the oil feed hole is from the pushrod cup?
While priming, does the oil make it from the oil hole to the pushrod?
Based on your pics I’d say no..... or if it does, not enough of it does.

Obviously verify all the oil holes in the rockers/shafts are aligned and oriented correctly.
But if you find they are correct, my suggestion would be to add pushrod oiling to your set up.
Which, depending on what some of your other components are, might just require new pushrods with holes in them.

If you go this route, you’ll want to use pushrods with restricted oiling.
A feed hole of .025-.030 would be plenty.

Edit...... just remembered this is a solid roller combo?
Not too many of the BBM solid roller lifters have a provision for pushrod oiling.

If you’re running spacers between the shafts and heads, check for excess leakage in that area.
If you’re running studs in the hold downs, make sure the ID of the holes where the oil supply enters the shaft aren’t restricting the oil flow(usually more of an issue with studs as opposed to bolts).