i have an 305 still with the tbi injection full intake( manifold with the TB ported and k&n filter)and full exhaust (shorty headers with flowmaster 3" y pipe with a freeflow cat and mufflers) i just picked a lt1 cam kit off a junk yard i want to go carb with a 350 block will anything interchange onto the 350 or am i basically starting over?

 

The LT1 cam is a factory roller type, so the 350 block that you get must be of that type. All of those blocks have one piece rear main seals, which your TBI engine has as well, so the one good part is your flexplate and starter will work on the 350.

Everything that bolts to the engine should bolt onto the 350. However, you don't want to use your L03 heads on a 350, so basically you'll need a 350 longblock and bolt your stuff onto it.