To elaborate a little bit;
The early chevies used a lot of 1/4-20 bolts for assembly,with the lifter cover,and later the valve cover being the most noted. This was the same size bolts used to assemble the wood stoves of the time.(My uncle told me it was common to find either the truck's engine sheet metal or the wood stove on the farms in his area missing bolts,pirated to make the other work.)
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