bbc big duke heads and timing

We have a 11.6 merlin pro block 4.500 bore and big duke heads and wanted to know what's the most timing we can run.This is a boat with a 1471 ssi at 60 % overdrive with a mag 20.

 

I have been told 32 max due to the small combustion chambers.

 

The smaller chambers want a fair amount less than a standard BBC, but we need to know cubic inch as the more inches, the less timing, and the more compression, the less timing, and what fuel are you running, etc. Plus, how much have the heads been cut, what are the cc's now, are the piston domes coated, etc. I take it this is a standard 18degree big duke? Running water in the heads?
That also seems alot of blower. Is this a pro mod boat?

 

I run a 565 with 18 degree Big Chiefs similar to yours. I run no more than 32 degrees at 22lbs of boost. Makes good power from 26 to 30 degrees.