Roller Block: Pushrods Rubbing Against Head

MOPAROFFICIAL said
If the heads havent been opened up , deep gasket match, then just drill them 9/16 and run it. Simple as that. It 90 bucks at rhe shop. Did this near same combo before.
'88 roller 360, used 974 casting heads from '74 . Runs a lunati. 585 hyd roller with mopar replacement rollers and spider.
All early casting heads need modifications to the push rod holes to run a roller cam.

Hi. This is a late reply. But I am basically running the exact same block and heads (well my block is an 89). I have my heads at the machine shop right now, and am trying to figure out my best move before I pick them up. This thread is very useful for sure, as I think a lot more people will be looking at this type of setup deliberately. Why? La heads flow better than the 308 heads, (Probably get some pushback for that) ;-) and people will be seeking out the roller block as a way to avoid flat tappet issues. I think the set up is a great idea, it'd be nice if there is a simple solution that is agreed upon by people who have tried different solutions.

So it seems there are two ways to fix this before assembling the motor. 1: Oblong the push rod holes to accommodate the needed clearance. or 2: Drill out the pushrod holes to 9/16.
Now my question to you, how did the 9/16 holes work out? I am worried about getting to close to the intake port, and will there be enough room to do any machining to the intake port for say gasket matching etc.? The gasket matching isn't a big issue for my build as I am not looking for a high HP build, but others will definitely be.

I am thinking of asking the machine shop to drill holes to 9/16 except for the intake pushrod holes and using a die grinder to oblong those ones (just in case I decide to use these heads for something different in the future ie; future considerations). Also what length pushrods did you end up using?

Thanks