You won't necessarily even have to change the ECU/Prom or injectors. I swapped in a 350 (crate motor for an 87 pickup) into my 87 IROC back in 1991. This was a MAF setup not speed density and all I did was use an adjustable fuel pressure regulator to bump up the pressure to 50 psi. Only other mods were edelbrock headers, 3" single exhaust, and a homemade ram air setup.
It worked flawlessly until I swapped cams. IIRC the new cam was a Blue Racer dual pattern with 112 lsa, 204/214 duration and .435/.465 lift. After the cam swap the car would surge a bit at idle and sometimes stall sitting at lights. Had a custom PROM burned at Arizona Speed and Marine which cured the idle problem but made the mpg nosedive and made no improvement in ET/mph at the strip.
I would think with the right cam and an adjustable regulator on a mass air motor you could do the swap without new injectors or a prom.