The throttle body EFI units are nothing more than a glorified carburetor to me.... but they are a tad bit cheaper if you go that route, the sequential unit like the edelbrock is better IMO.
Switching over is costly... $2200 for the edelbrock unit, $380 for the '87 MC efi tank that includes pump assembly, the need of an aftermarket in tank fuel pump, cost depends on what you find and decide to use, all new braided fuel line hoses(supply/return/vent), AN fittings, and all thats before taxes, at least this is what its going to cost me so far just to give you an idea what you're lQQking forward to as well.