So I bought a 94 with a 350 that's locked up. I have a rebuilt 350 from a 79 GMC on the shop floor. What all do I have to switch over to put the TBI setup on the 79 eng? Do the heads need to be swapped?

I know intake, distributor and accessories for sure. The first issue I can see is there isn't a spot for the knock sensor on the 79. I'm also not sure on the starter bolting up. I'd also remove the mechanical fuel pump and install a blockoff plate.
The 79 eng was an auto, the 94 has a stick (just use flywhl off 94 eng) I'd like to have the engine out of the 94 tomorrow or the next day and then I will know more.

 

try reading some of the older posts, there are quite a few about swaps like this, i do know that the intake will have to be modified for the older heads or swap the heads if they look good, crankshaft wise the 79 is externally ballanced and the 94 is internally ballanced, that may cause flywheel or clutch issues, not for sure, on the starter find one that bolts to the block and remove the solenoid so you can engage the pinion by hand to make sure it contacts the teeth all the way, keep us informed on what your up to or up against

 

I was told if the 94 is non-vortec (which it is) the heads don't need to be swapped.
I didn't know about the balancing.

 

the 4 center holes on the intake are drilled at different angles on an engine with TBI vs an engine that is carburated, therefore you can either swap the heads or will have to modify the intake

 

I think I will pull the pan on the '94 engine and see how much damage there is. I might just put all new bearings in it and put it back in. Rod bearings are inexpensive ($20-30) and I don't think mains are much more than that.

 

yeah if your lucky all you will have to do is have the crank turned and the rods bored and resized