i have an 89 formula with a 305 tbi and i was wondering if i will see any improvement in switching to carburation or would it just cost alot and not do anything. what do u think

It would most likely be a waste of time and money. It's better to wait until you atleast have a 327 to drop in. Even better for 350 and up.

TBI to carb is probably not a very big difference, you'll probably get better high end power (up to 5000-5,500 RPM) and possibly better throttle response. It wouldn't be massively expensive (maybe 400-500 using new intake and carb as opposed to used parts) You would need to ditch the computer unless you swapped in an L69 setup with Q-Jet or another CC carb. The only disadvantage is that warning lights will no longer work. Carbs are easier to work on (not necessarily savings in time, but less tools and elbow grease needed). If you ditched the heads and put on a carb, you'd probably see a significant change in power. It really depends on your future plans, but if you bought a 650 or 700 CFM carb and intake, you could also use that on a future 327-383 (maybe even a 400 SBC). Coming from someone that hates EFI, I'd recommend the proceedure.

But, you could get a high performance TBI injection system from Holley, that would also boost power... probably cost about the same as carb, intake and heads though.

You'll definitely need some detailed instructions and confirmation of my info, but the swap isn't very complicated.