looking good! you should drag that engine up for my burb and check out dad's "prototype duramax" (chevy with an isuzu in it) it is an inline 6 turbocharged from a 1976 low cab forward coupled to the original 5 speed, and hooked to a 3 speed brownie. it is in a 1979 RCLB 2wd C3500 camper special that was originally BBC turbo 400.
the swap was done horribly by the PO, wiring is a mess, guages electrical taped around the steering column, etc. plus a nice spray paint paint job to boot. but the truck drove nice and got 23 on an unladen empty run, and towed well.
hope your swap turns out much better, but as shown by all your projects, I'm sure it will be close to SEMA worthy! btw, why wasnt a gas burb used for this project? I thought I would be cool to keep this one original, then find a gasser twin and do the isuzu swap. identical rigs, one OEM configuration, one highly modified custom.