I was tired of the old 2.8LV6 it was leaking oil almost from every seal (I've heard a common problem with this type of engine) so I decide to junk it! I begin the search for a more powerful engine, I was searching for a 5.0 (305)V8, 5.7 (350)V8 or a 4.3(262)V6 which is based on the Chevy V8 small block (same bore and stroke as the 350) and has many common parts with the V8 small block. I found a wrecked 1988 C1500 pickup with a 4.3TBI and a turbohidramatic 400 along with the ECM and wiring harness. Then a contacted a few people on the internet who gave me their advice on how to install this engine. You can find many people who can help on discousions groups, on truck related sites and mailing lists. The easiest way is to contact company such as Advance Adapters who has the frame mounts and other adapters that would be needed for the swap. But I am outside the US, in Central America and its very difficult to bring these adapters home.
I used the original rubbers attaced to the engine and weld some metal legs to the frame to screw the rubber mounts in. I encountered that the original exhaust manifold would interfeer with the stearing colum so I found a shop that would make custom headers to solve the problem, if you are on the United States you could find a lot of custom made headers to fit the situation.
Then came the electrical part. The 4.3 from the truck a found was fuel injected through a TBI 220 unit the same as the 1986 2.8. The electronic control module is the same for both only with a different PROM. I used the 4.3 complete ecm and the 2.8 original wiring harness, I just needed to extend some wires becuase the 4.3 is longer and wider than the 2.8, so i cutted the ends of the 4.3 wiring harness and join them to the original wires.
I used the original catback tubing , fuel pump(low pressure, in tank pump) that came with my truck and the 4.3 accesories like the a/c, power stearing pump, alternator controled with the original relays and controls.
Hope you have found some ideas to put in your truck. Don't forget that if you can think it, you can do it. Email me if you have any questions, ill be glad to Help.