I used '89 S-10 buckets in my '57 GMC,just cuz I had 'em and the stock seat was trashed. Comfortable enough,but a real hassle to install. The sliders are not at all concentric,so each hole had to be drilled specifically,and had to be lifted about 3 to 5 inches to get the seats leveled. I don'r recommend 'em if you have any other options open to you.
Speed

1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck