So you want 2 go Big block...Read this first!

I dont know about you but I wouldnt want to try and stop even a 350hp small block with 9" drum brakes. But I do know someone with a 12second B body with drums still. Yup, Its a 440

If I can cool a 11:1 compression 340 with a stock 22" radiator you can cool a big block with one.

a 7-1/4 rear will blow up behind a stock slant 6 if you beat on it never mind a 340 or 360 with a few mods, 8-1/4s are good for around 400hp, just dont launch it with slicks. The 8-3/4 will start breaking teeth of the ring gear eventaully, Ive seen it happen with 12 second small block stick cars

Summit Racing has an exhaust kit for $200 in 2 or 3" size. Same price for either.

I dont know the cost of Big block 4 speed parts but I do know clutches, shifter, flywheels and Saftey Bell housing all cost the same big or small block.

You still didnt say if you started with a slant 6 or a small block car ? Big difference there.