GM/Chevy guy for 50 years.
My work had bought 2 new Chevy C10 LB work trucks. Both 350's. a 1976, and a new 1977 when I started doing service. The '76 was a straight up Beast. My '77 was smooth and tame by comparison. Night and Day difference.
So. Lets talk Chevy V8 engines!
Chevy truck/van motors can be sourced from Detroit, or Tonawanda New York. I think they built the SBC there in NY too. I know Chevy built BBC motors came from both plants in the Vans. Beginning in 1990. Are they better engines? Tonawanda seems to believe so, as per their BBC valve cover badging. As per Chevy SS 454 pickup.
Canadian built BBC Vans, 1st digit VIn # 2. Big Block 7.4/454 motors came from Tonawanda. IDK if all the other SBC Canadian built units had Tonawanda motors.