no problem Clay, I am glad you asked.
well nothing ventured nothing gained. I started by cutting a large hole in the firewall and trimming to fit.
IMG_0546 by
Joe Doh, on Flickr
IMG_0547 by
Joe Doh, on Flickr
IMG_0549 by
Joe Doh, on Flickr
well I'll be dipped.
IMG_0551 by
Joe Doh, on Flickr
IMG_0552 by
Joe Doh, on Flickr
IMG_0548 by
Joe Doh, on Flickr
everything fits. the interior distribution box JUST clears the cowl vent mechanism. you can still check the trans fluid and add oil, and put all the blower housing bolts in. even the stock heater and AC hoses will fit. I already know how to put the AC condenser in front of the rad, I did it on the last 49. I am literally a small firewall trim and some fiberglass work (to mount the blower) away from having actual defrost, AC, and heat, working from the stock s10 controls. I am gobsmacked. I think I spent more time fiddling with the last vintage air system and still didnt hook up the ac (hoses were incompatible with the s10 stuff)
I think I can have this buttoned up tomorrow and start on either rust repair on the cab or mounting the front sheetmetal. I beat around on the fenders a bit the other day, that stuff is as tough as I remember. I have most of a GMC clip in the back yard but I want to use it as a last resort.