This was from an engine builder.
They are just the simple Vortec's that everyone has, just pocket ported some under the valve.
Should be pretty simple to have a competent shop perform the needed grinding.
I was getting all conflicted with amount of info since I'm trying to put vortec heads on a non vortec block. Between air gaps, toes of intakes, different bolt patterns, the right EFI, nothing close to a straight answer, many variables. Some say high vain or low, high for low flow. Ensure you get the correct one for low temp area since I live in the Northeast I have to be concerned with have the proper air flow for temps less than 40 deg.
The heads from summit as you suggested seems to be a good fit, it's the intake that's the issue now.

...... Damn build. Lol
Lots of research to be had on the internets.
As far as I can see, the Summit branded "Vortec" heads are the ones I would go for at this time.
They are new and have extra meat where the factory ones could use it.
Here is a link:
https://www.summitracing.com/parts/sum-151124
Do some reading as it should be pretty simple to build a stout engine with these and the right camshaft to compliment them.