I doubt that anyone has done anything remotely like this.
Some Google searching suggests that the 292 bellhousing pattern is the same as a 90 degree v6 and v8s. You didn't say what engine was attached to the trans. Also, you may have some problems that the number of splines for the input shaft, clutch, and slave cylinder....
Why are you wanting to use the straight six?
I think the big ugly S10 steering box out at the front of the frame is gonna be hard to hide. I think the frame will be way too wide in the cowl/ cab area. you may have to get rid of the 'hips' in the frame behind the front wheels.
If the T-5 was behind a 4.3 you're in luck! I would love to have a 292 and a t-5 for my nova!
I had a low cab 36 Chevy pickup a couple years back; but had to sell it due to finances. I was going to build a traditional mid-late sixties hot rod out of it; but had looked at my old S10 for a frame (the '36 was currently resting on a Ford Ranger frame......but the stock frame was in the back of my garage for it). The S10 frame did appear to be wider; and you can't hide the bulky modern suspension too well under the vintage pickup fenders! LOL! Not to mention that it was a fair bit wider then the width of the '36's bed. Personally, I wouldn't do that to a '36......and was going to box the original frame and stick with the straight axle.