[elhigh]

I think it's an interesting idea, a hybrid fullsize SUV with the electric assist on the fronts. If you were to start with a 4wd Sub you'd have all the front-drive hardware in place. Do the necessary mods to isolate the driveline to the rears for conventional RWD operation all the time, and then hook up your electric drive system to the FWD components. I think you could even retain the low range on the transfer case, you just wouldn't have it anywhere but the rear wheels.

Downsides: weight. Electrics don't love weight as you know, and you're looking at one of the heaviest vehicles available on the conventional consumer market. You'll pick up at least 200 pounds, probably a lot more, just switching to the 6bt. We haven't even talked about the additional weight of the batteries or electric motor yet, not to mention necessary suspension upgrades to contend with the added weight. It snowballs pretty badly.

Aero: the Sub is a big box. Even if it had great aero - which it doesn't - it has the surface area of a small garden shed. So even with a good cD you'll still have a lot more cDA than a smaller vehicle. Your electric range will be necessarily short.

Complexity: Since the 6bt was never stock in the Sub, you have an uphill climb just to get started, bolting one of those in. And THEN you would be adding the electric drivetrain. You must really enjoy turning wrenches. A project like this implies almost endlessly deep pockets, too.

Physics: the 6bt is about 38" tall, 5" taller than the 454. You might not be able to stuff it in and have the FWD components too. One or the other. I dunno if there's a different oil sump available that might free up the space, or if you'd like to do something bizarre like fit up the diesel with a dry sump oiling system. I don't know if that's even possible.

Upsides: room. Engine height excepted, there's a fair amount of space under the Sub to install battery racks while still maintaining decent ground clearance. Bear in mind you'd probably have to sneak the electric motor down there somewhere, too. If you're willing to skip the spare tire that may free up some space for batteries. With over 5000 lb. curb weight, you'll want all the wattage you can stuff in.

Familiarity: You won't be the first guy to shove a 6bt into a Sub, so there's some established wisdom you can call on.

You wouldn't be the first guy to build an electric truck either. Mixing the two, well - that's different. You might be blazing your own trail there - and sometimes trail blazers don't make the news except as Missing Persons reports.

My take, for what it's worth as a mere commentator: I say bolt in the diesel if you're bound and determined, and make the tuning and aero mods necessary to wring every mile per gallon you can out of it. Skip the electric drive option as a blue sky scenario, or maybe spend some time building an electric compact truck for running to the co-op in. Builds of that nature are pretty straightforward and, by the look of them, a lot of fun. I just fear that trying to do everything on something like a Sub will be an exercise in frustration.