I have started conversion from 350 5.7 to 350 i ttook out of 74 impala...
I have three issues...
#1 the tranny will the cadillac tranny hold up...
#2 fuel pump issues if i keep caddy pump...(regulator or electric Pump)
#3 I keep hearing issues with tranny and other things with computer... do . I need computer if i'm using totally carb motor no intake conversion...
Last one what othe rissues do i need to consider...

What kind of caddy are you putting it in. I dont think the trany will work. use the tranny from the 74. You wont need the computer.

1991 brougham

I dunno Fasstwood, the tranny ought to bolt right up, but the older engines flexplate will be larger. I'm not sure if it clears the bellhousing. He will need an early 80s flexplate,[small dia. 2pc. rear main]. I'd try to keep the original tranny. Swapping that will be another set of problems that will be worse than the engine.
Another thing worth noting, I put a pre-77 [large frame] 350 into an 84 Caprice and found the brackets on the engine were wider. They didn't look too much different at a glance, but they wouldn't land on the pads on the frame. I had to jack it back out, and pull the brackets off the 305 I'd taken out.
You don't want to try and run that carb on the TBI fuel pump, too much pressure. You're probably gonna need to get a regular sending unit from an older car for your gas tank and get that pump out of there. You're retrofitting that baby to the 1970s. Even with the ease of Chevy interchange you're gonna get some surprises. :banghead:

What tranny do you have? I've got a 2004r which has a BOP bolt pattern and bolts up to just about any GM v8 or v6 engine of that era. Mine was connected to the HT4100 which I swapped for '91 350 later. I had to toss the TBI and go with the Q-Jet carb which is fed by original electric pump, it's only 10 psi if I'm not mistaken. You'd have to check how much pressure does your TBI have though...