Some bad idea's never seem to die. This facinates me. I frequent many automotive formus and in all of them there are few re-occuring aspirational topics that resurface now and then and quickly go no-where. They all start this way with a declaritive, enthuiastic, pie in the sky post from a new memeber, then the encouragement from the faithful and then radio silence, with the OP never to be heard from again.
Let's get to the reality of the situation. There will never be a vialbe Vintage electric GMC motorhome.
Anyone with the knowledge, skills and abilities to pull this off would also understand it's idiotic and a fools errand.
Let me expain it to you by real world example. A Tesla cyber truck with every modern technical advantage, designed from the ground up to be an efficient EV has a real world effective range of 115 miles towing a basic camper flat. Head up to a mountainous area, it would be considerably less. As a DIY retro-fit project you would likely need double the battery capacity to get 1/2 the range. That's where the weight spiral sets in. With the A/C on in the summer you'd be lucky to get 60 miles before neededing a lengthy break at a high capacity charger. Hopefull there will be one large enough, just waiting for you at the exact spot you need it along your route. Spoiler alert... Not gonna happen.
Did you even do any back of the envelop calulations? The amount Lifpo battteies and copper wiring alone will cost well over 200$ per Kwh. Multiply that by 200 Kwh and you quickly get to $40,000 for about 60 to 80 miles of range as a DIY project. With conservitive public charging at $0.30 per KWh you looking at 60$ to go maybe 80 miles if you're lucky. Even at CA gas prices that still buys you 10 gallons of gasolene and will allow you to travel about 60 to 80 miles in a well tuned as-built GMC motorhome . None of this accounts for the cost of the controllers, electric motors, fabication, junction blocks, fuses, safery equiptment, systems integration, cooling, heating and many other costly issues that will also need to be accounted for.
The Tesla LDU has a peak torque of 332/ft lbs. That's far less then the Olds 455 and would be like swapping in a Olds 350. Major down grade. Using the LDU at or near it's torque capacity for long periods of time will casue it to fail quickly.
So you want to camp fully electric?
Option 1 - Get a used Cyber truck and a 2nd hand light weight travel trailer and stay close and hope it all works out, It might, it could, and you can be in you favorite near-by camping spot in 30 days or less for about 65k. If it doesnt work out, you'll likely be able to resell both and re-coupe most of your money. Trying to DIY a fully electric vintage GMC, never gonna happen and you'll waste 50 thousand dollars and years of your life trying with nothing to show for it.
Option 2. Get a Chevy Brightdrop (50k) and convert it to a camper. Still will only get 150 miles of range and budget 10K for the camper retrofit. Chevy already killed the platform so good luck getting parts and service a few years from now and few dealers will even touch a highly modified vehicle, so you're entirely on your own with this option. But... it's possbile... and might be worth 1/2 the sum of it parts IF executed well.
