['76 Big Block]

I have some problems with space/room in my '76 as well, although for me, the problem is getting my long legs beneath the steering wheel when getting in.
I'm 6'6"----right at 250 so not a small person...
Anyway, I had an '81 GMC step side with the factory steering wheel, and never had a problem getting in or driving.
My current truck has an aftermarket Grant steering wheel, that I bump my knee on sometimes getting in, and after I'm in, the cab still feels crowded with the seat all the way back.
Maybe the cabs got roomier over time?