The motor is currently in my 240z that I am selling and putting this motor in my 69 Camaro.
It put down 275rwhp and 280rwtq. The jetting was pig rich at 10.0 a/f ratio across the rpm band.
Also the timing was set at 33 deg total. I had no tools or jets to make changes. Here is what I have:

355 sbc
approx 10 to 1
forged flat tops
AFR 195's 68 cc straight plug
RPM air gap intake
3310 holley 750 vac sec
286/490 comp magnum hyd
1.52 comp rollers
proform HEI
1 5/8 blockhuggers 2.5 collectors
non manderel 2.5 dual exhaust
magna flow x pipe
spintech muffs
14x3 k/n
TH700r4

I figure with bringing the timing to 36 total and jetting for 13 to 1 a/f ratio will probably only give me maybe what 290rwhp?? Shouldnt this set up make more power?? Do you think with longtubes/dr gas x/3" mandrel I will pick up a bunch of power??
Can this set up get me into the soild 12's??

Man, don't worry about those dyno #'s. Just get it tuned right and the #'s will fall where they may. My 67 Chevelle had a very similar motor with ported twisted wedge heads, and little more cam (hyd-flat tappet), and 3" exhaust. Only made 315 rwhp (corrected) but ran 11.7-11.8's at 3380lbs.

You've got plenty of motor to run 12's. Your rear gear, converter, and traction will determine if you do or not.

Good luck.

I may be optimistic, but I wouldn't be suprised if that combo picked up 40-50hp with a good tune up on the dyno. I've seen it time after time.

I agree, with a good tuneup it should pick up considerably. I would expect maybe 325 RWHP with your combo . . .