Expert: William Forster - 8/30/2008

Question
Hello,
I'd like to know will a 4.3 engine fit in a 1973 Chevy 3/4 ton (c-20) 4 speed? Also, how would you hook up a fuel injection, computer, motor supports, etc.?  

Answer
Yes, it will fit, but I doubt it will pull around a heavy vehicle like the old Chevy 3/4 tons- especially if it's a 4 wheel drive. The swap will require a LOT of modification- an electric fuel pump FOR STARTERS. a COMPANY OUT THERE CALLED PAINLESS WIRING SHOULD BE ABLE TO HELP WITH THE WIRE HARNESS. when YOU GET THE DONOR ENGINE, YOU WILL NEED TO YANK THE COMPLETE WIRE HARNESS AND COMPUTER. Sorry, caps lock. Anyhow, you will need to tell the yard you want a 4.3 with a computer cut- they will sell the entire harness to you. You will surely need at least part of it. I suggest going to a magazine like Truckin' or something like that for a tutorial on how to do the swap you want, or they can lead you to a publication who can help. I'm a bodyman, this is really outside my expertise- but I've done two 6 to 8 cyl. swaps. Chevrolet trucks are the easiest to perform these swaps on, and there is a great deal of interchangeability between the various years. The nuts and bolts will be easy- the electronics will be difficult. Be sure you have a perfectly running engine before you start, one you personally heard run. This will help during the inevitable de-bugging process. Expect set backs, and to probably need professional help. Good luck!Bill