Here the trade offs that you would need to consider:

Carb install

1) fab an intake manifold
2) install an electric fuel pump (4200's never came with a mech pump)
3) for a TH350 etc. get an adapter plate/mid engine plate T/C
4) mod the trans to accept the starter nose.
5) get a dist. install kit from Jerry W.

The rest is common to an efi install e.g. engine mounts, rad, PS hookups etc.

EFI install using GM electronics & stock 4L60E

1) get the engine, gm harness, PCM, transmission
2) send the PCM to someone like limequat who has HP tuners box and get it modified
3) wire in the harness to your vehicle
4) run a EFI feed and return lines to/from your tank
5) install an EFI fuel pump and fuel pressure reg.
6) get a conversion box to drive your speedo (4L60E never came with mech speedo drive).
7) install the drive by wire gas pedal.

The rest is the same as a carb install.

So which way would you go?

Edited by efi-diy (01/08/11 09:38 AM)
51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them