Dyno'ed My 360..it's a pig..what next?

I would not spend any money to swap parts until you optimize your current combination. Getting the AF dialed in along with the timing should pay good dividends. If it would make you feel any better, your car would have dyno'ed 40-50HP higher with a 904. versus the A518. The race track showed me swapping in a A500 in place of a 904 cost me 40 HP (4 MPH in the 1/4 mi). I bet a A518 takes more HP to turn then a A500.

HOT ROD did a dyno test on a '98 Dakota that was rated rated at 250 hp at 4,400 rpm and a whopping 345 lb-ft of torque at 3,200 rpm that demonstrates the losses associated with the A518/A500 trans:
"Our dyno test (see "Modern Muscle: Who's Jivin' Who?" May '98 ) showed that the R/T made 191 hp at the wheels."