Help with Chevy 6.2d and th400 parts

Hi mertzman, sorry for the slow reply, I've been off-map for a while, sorting other life & vehicle issues!

Thanks for the offer, I'd really appreciate it.

The thermostat housing seems to have these part numbers - Dorman 902-2052, or alternatively 14028918, 84987, 6209, 814987
The Dipstick and tube seems to be something like 890-743802, but mostly I can only find them as manufacturers part numbers such as TCI 743802 . It's the standard TH400 GM/Chevy dipstick, not some fancy flexi kinda thing. I'll need the rubber seal for the bottom too.
These two things are the really important bits, and while they're probably fairly common over there, you can't get them for love or money over here!

I'm loosing patience trying to find the right Torque converter - all the ones I can find for High-torque applications don't lock up, which is no good for long distance cruising. Perhapse you could just ask your parts guy what he'd recommend for a TH400 on a chevy 6.2 in an RV? As far as I can work out, I'm after a 13", lowish stall speed high torque locking converter.
At this rate though, I'll just shell out the $330 odd to have mine reconditioned over here.

Again, many thanks!

Just to be sure, we're talking 6.2 gas? Or the diesel? I'm a VW/BMW guy nota Chevy guy!