My 360 build.

Flat top pistons what compression height?- what is your deck clearance?
we need to be able to compute compression with the available heads how close to the ragged edge do you want to be with fuel requirements
check the deck clearance at all 4 corners to make sure you do not need to square the block up
did you say what your weight is?
on your car is the chassis stiffened- do that before adding horsepower
lots of good tips above
get the best head you can afford
maybe a ported midsize head as opposed to a big port head to keep the velocity up
for a hyd in the 230 range comps XE 275 HL would be the target or HR274HR does slightly better Engle K 58 hyd
If HR I'd recommend an inverse radius flank HR from Mike Jones you will need head flows let us know what he says Street Performance | Jones Cams
did you say what headers
what rockers- ask mike if 1.6 esp on the intake would help and what springs
clearance your new heads for 3/8 pushrods