Last year i swapped a 97 obd2 5.9 w/fac efi and over drive trans in my 48 plym. Fuel delivery was a hurdle but not a big deal, inline efi pump w/a ls1 filter reg. Motor/trans was already retrofitted in a street rod before i got it so i didnt hafta sort a full wiring harness. It runs circles around the 355 that it replaced!
Just finished up a 01 5.9 carbed w/ airgap and edelbrock 600 in my 88 w250 pick up. Runs good but not as good as the 48? Both were supposed to be low mile motors.
Efi in my opinion would be way to go