1983 G20 van build - looking for advice

[drainoil]

I love full size vans. Now I've never had to do an engine swap in one so if I did, maybe I'd have a different opinion. My dad had a brand new '77 E250 cargo van that he carpeted himself and put in nice comfy seats. Even had chrome side pipes on it. Our family took it all over the country on trips. Too bad I could only see out the windshield as there were no side windows behind the front seats.

My '94 conversion van (with rear windows) only gets driven when I need such a vehicle. My vx gets driven for everything else. So two vehicles that allow me what I need when I need it. Purchase price of both put together was under $4500. Insurance and license tabs are cheap. Only had to do general maintenance on each so no big repair bills. Best thing is I haven't had a car payment for the couple years I've had them. If your into the keep up with the Jones' crowd these vehicles are far from desirable, but they work for me. Oh and I can haul more stuff in my full size van than my buddies newer Suburban (that he pays over $500/month on).

[kv1]

Popular opinion is against chucking the 350, and I agree that it is not financially rational. I just got my paycheck though!

I think I am going to go with the diesel route. The engine has a 400TH transmission on it, but like everyone suggested I will probably upgrade to an overdrive transmission (700r4) Looks like a rebuilt 700r4 costs around 750 dollars. I will probably end up upgrading the transmission after I put the diesel in and make sure the engine is alright, and try biodiesel with the current 400TH trans.

What appeals to me right now is driving on cooking oil, to me it's hilariously awesome.

What about upgrading to a manual 5 speed? What trans would bolt on?

@drainoil, that's really smart. I have a bicycle and a motorcycle that I use to not drive the van.

[spacemanspif]

Not sure on the manual but there is probably adapter bellhousings to put pretty much any trans behind any engine. Switching from gas to diesel is not a run-of-the-mill engine swap and you may need to consider changing rear gears. Usually 3spd cars came with numerically low gears because 3rd is 1:1. However, old diesels rev to ~3500RPM, right? if you have 3.08:1 rear gears and keep your 3spd trans you may run the diesel too high on the highway to get the MPG benefit; pretty much requiring a trans with another gear (or 2, but 6speeds are expensive), or a rear gear change.

[Gasoline Fumes]

The 6.2L will bolt to any transmission that the small block bolts to. But I don't know if the transmission mount or driveshaft length will be correct. I'm also not sure where the shifter would come up through the floor on a van. I'm guessing the manual vans were column shift and likely only 3-speeds.

A 3.08 rear end is fine for a 6.2L without overdrive. But obviously better with overdrive.

Do some research on running used cooking oil on the 6.2L. The DB2 injection pump is pretty fragile.

[kv1]

At what speed would the overdrive kick in with the configuration with a diesel?
Thanks for the tip about the pump being fragile. I'm probably going to install a dual fuel system with heaters for the fuel. Like here:

https://www.youtube.com/watch?v=D157-bJtY08

[Hersbird]

I think you are crazy putting much effort into something that old especially if it is not in very good condition otherwise. I have never done a van motor swap but think I would do it this way if it were me. Lift the body off the frame and then roll the motor out on the frame and wheels then have all the room your would ever want to do the swap. However the factory puts the motor in, is how I think your should take them out. On unibody cars that means the assembly comes out the bottom, on something with a full frame often the whole front "clip" will come off, on a van I'm sure they must assemple the frame and running rear and then add the body on top. Like this video

https://www.youtube.com/watch?v=JxVa1zQLN1g

[2000mc]

The 6.2 diesel was an option... I think you would be far ahead selling your van and buying one that already has the diesel. Could a smaller van fit what you're wanting to haul?

[kv1]

@Hersbird thanks! Yeah that's already what i was planning to do. Hope the body comes off easy.

Regarding a smaller van, no not really. Since it's for construction, the bigger the bed the better really.

With regards to selling the van, that means that someone else will drive it and burn a lot of gas. Plus diesel vans that are on the go are 5k+.

[2000mc]

Diesel, $1800, trades some aero for extra cargo space.
1983 GMC Diesel g3500 box truck, priced to sell

[kv1]

That's a much larger vehicle... it's a dually truck! Plus it has 200k miles on it =/