The intake port looks close to being flush. Might clean up @ .010-.015"?

Are you using stock size valves on this head?

That is pretty low compression, too bad you cannot find some other pistons w/a higher compression height.
There might be something available.

What CC's are the chambers supposed to be?

I believe anytime you can create a better short turn radius the better the head will flow.
That is why I suggested some lumps.

Factory Pontiac V-8 heads flow pretty crappy. Even the SD heads have a lot to be desired.
The Edelbrock heads flow much better.

Nice pic of the cutaway OHC head. THX.

The OHC head looks like you could raise the intake port & it would be a good candidate for the floors to be filled in with brazing rod to improve the intake floor short turn.

That is the way I see it anyways.

I think part of the reason the OHC head flows mostly on the long turn radius side & why they need opening up on that particular chamber area is because the short turn radius needs a lot of improvement.

What degree is the OHC valves canted back?

SBC are 24*,

If you look @ the short turns radius's on the LS heads, they have huge never ending short turns.

When there is no good short turn radius, the air naturally follows the long turn side, if there is not a good short turn radius, the air will be more turbulent & not follow it.

Canted valve layout looks like a typical SBC to me.

GM learned it is better to have the valves more upright than canted, they just raised the roof & also the short turn followed.

It allows for more valve lift, that is why our 194-292's can go w/a pretty high lift w/out the valves coming close to the pistons, the valves are more upright, but our ports suck also.
That and Siamese ports suck.

12 port SDS EFI