The most power I made on that 470 was 775 hp with the TF270 heads. That was with flat top pistons and pump gas. To pick up the extra power I switched over to a Wilson ported Indy intake. The OOTB Indy intake didn't work all that great but once Wilson worked it over it made really nice power. Cost a ton of money but that is how it goes. We ditched the dry sump system and switched to a wet sump setup using a high end Moroso pan and an external belt driven oil pump. The oil pump has a vacuum pump mounted on the rear of it so they were both driven by the same belt. Kind of a cool setup but once again, kind of expensive. Anyway, with the vacuum cranked up to 15 inches the engine hit 775 hp which is pretty good for those heads.
We built a drag race 505 with the TF270 heads. Big roller cam, high compression, etc. but it didn't make as much power as my pump gas 470. Not sure why, probably because the camshaft wasn't "perfect". I did a fair amount of camshaft testing with the TF heads and they are picky about what they want. Duane can steer you in the right direction if you decide to use TF heads.
https://www.motortrend.com/articles/dyno-tested-vacuum-pump-help-engine-make-power/