A 512 with TF240 heads, modest cam and 3.54 gears seems like a great street combo to me. You probably have 600 ft-lbs of torque if you have a decent exhaust and the engine is tuned properly. I wouldn't be in a hurry to mess with that combo. Maybe get it on a chassis dyno sometime and see if you can tweak a little more power out of it. If it was mine I'd put a Sniper EFI kit on there rather than spend the money for 270 heads. With a Sniper you can dial the tune in and you can stay on top of it by watching the data logs.
I posted my dyno session at the end of April. It made 491 at the tire. It's got 1 7/8 ttis and a 3" X-pipe exhaust with Ultra Flows. I'll be adding an AFR gauge when I get the exhaust tweaked how I want it. Efi might be down the road.
