Looks like it has 587 heads. You have block and heads to run high 9s at 3100lbs. Even if they are 596 head castings they are fine. Sonic test block. Reject it and find another if major thrust will be less than .187 and .160 minor after boring. No fill needed, just makes the block a heavy pig. Restrictor tubes and oil pathway mods a good idea. A QMD port job and good guide and valve job and of course good valves and hardware. Program 2 bolt caps on middle 3. A steel 4" or 4.125" crank, a set of 6.25 rods and flat top pistons about .08 above deck, like a factory 340, just taller. A racer Brown STX22 solid flat tappet cam. Victor intake. Basically a copy of engine in my Demon. Passed 2100 runs this weekend at Beacon Dragway. Pistons never removed from the block and no valve job since original assembly . Went 6.22 at 108.50 Saturday night, and made a near perfect run first round today with no time run. .0000 on the tree and 6.2410 on 6.24 dial. Best engine I ever had! And in the 1980s everybody told me 360s were junk, don't waste your time and money on them. Runs best with 28* timing, crank trigger.