Chevrolet or GMC? Chevrolets were all 235s on the factory 4x4 trucks ('57-'59), though I suppose one could have had a NAPCO system installed on the V8 truck aftermarket.
GMC, on the otherhand, did offer a V8 option on their 4x4 models starting in '56. US spec GMCs used Pontiac V8s, but Canadian spec trucks generally had Chevrolet engines, so it is possible that a Canadian spec GMC 4x4 could have a 283.


Bill Burmeister