Daniel, IIRC - the length on the GMC 6 is about 3" longer than the Chevy 261. This previous conversation on comparing Chevy 261 and GMC 270 seems to confirm that. The GMC 228 shares the same external dimension as the 270 as far as I know. Others will be along to add further details soon I think. smile


~ Dan
1951 Chevy 3 window 3100
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"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)