Which method to increase compression? (Long)

[66P51GT]

I'm building a long-rod 302 and by the numbers, it looks to be producing a compression ratio of 8.8:1. Ideally, I would like compression to be 9.5:1 or thereabouts. I have two choices, deck the block or shave the heads. I don't know what to do. Suggestions and Pros/Cons would be appreciated.

Engine Details - all components are new including block

5.0 roller block with standard 8.206 deck height (4.00 x 3.00)
Ported Performer RPM Heads 60cc chamber
Custom Flat top pistons with valve reliefs (5cc) 1.522 pin height
Custom Forged H-beam rods (5.155 Long)
Felpro gasket 4.1 x .041

I did a mockup last night and don't have the right tools to measure deck clearance but it is close to .030 from the top of the piston to the deck.

I can either deck the block about .030
-or-
Shave the heads to drop 6cc to get to where I need to be.

Both seem a bit excessive. If I don't change anything, how much HP am I leaving on the table? I've seen different variables used to calculate HP gains per compression point from 4% - 11%. Experts please chime in.

Thanks!!!

 

[dastang2]

i am getting a set of 67 289 heads, they have 54 cc's and will raise the compression up to 11:1 i was told.

 

[giddyup306]

Or you could get different pistons.