I'm going through a similar swap at the moment, albeit with a 4L60E. This is my first swap on anything, and I suppose the important questions are:
- How much time are you willing to spend?
- How much money are you willing to spend?
- How much brain damage are you willing to sustain?
I don't have the time to spend, so I went the easy way and bought everything to not only do the swap, but to replace the suspension, steering, and braking systems.
You're going to need engine mounts and transmission mounts. I recommend Dirty Dingo because they're adjustable and give you inches of fore-aft adjustment. If the 6L80 won't fit into the transmission tunnel, you'll have to do some sheet metal work if you don't have adjustable mounts. With adjustable mounts, you can move the engine/trans assembly forward and cross your fingers that it'll fit.
I also can't afford any more brain damage, so I bought a harness for my exact combination. My harness was made by Howell. I called them and told them what engine and transmission I have, what it's going in, my gear ratios and tire sizes, then I sent them the factory ECU. About two weeks later I got an ECU and a harness for my combination with every connector labeled. The hardest part about wiring the drivetrain was fishing the harness through a factory hole in the firewall and figuring out a place for the ECU.
As others have mentioned, you'll need an EFI fuel tank. I bought the entire setup from Tanks, Inc. There's a woman named Georgia who works there. She sounds like my grandmother, but knows pretty much everything about EFI conversions. I got a gorgeous clear powdercoated tank with fuel pump and sending unit for not much more than piecing the stuff together myself.
I have an early 5.3 and the fuel pressure regulator is built into the fuel rail. Yours doesn't have that, so you'll have to get a regulator. Kits with AN fittings and fancy braided hose are obnoxiously expensive. You can get a Corvette regulator that will work.
Now that the fuel system and electronics are mostly done, you need to figure out how you're going to get all that information to you. You can get a module for a few hundred dollars that will convert some electronic data to analog to feed your cluster. I looked into it, and once I got to more than half the price of a new cluster, I stopped counting and bought a Dakota Digital system. It's complete and easy. The unit will read data from the CAN via OBD. Howell put a second OBD port into the new harness so I can use one for diagnostics and not have to unplug my dash.
In short, you can spend a lot of time and get it done cheaply or you can do it quickly and turn an $1,800 drivetrain into a cash bonfire.
