Picked this up recently, guy said he removed it from a '48 GMC "Big Bolt" with 270 but he thought the 270 was a later one. I noticed the bellhousing bolt pattern was slightly different than a bellhousing I have from a later 1/2 ton truck 270. Also what does the -1 denote & what does the "For GMC No. 2241891" refer to? Thanks in advance.
2241891 is a GMC part number for a 1948 and older GMC. It will fit in place of a sliding gear 4 speed or a stick shift 3 speed which made it a desirable transmission 70 years ago to make old pickups go faster. It worked in both Chev and GMC. Between 1947 and 1948 GMC changed the bolt pattern to the clutch housing when they came out with the SM420. The older clutch housing also has different mounting than the later one. All 228-302 series GMC engines have the same bolt pattern to the clutch housing. It would bolt right into the 1941 and 1946 models shown but not the late 1948, the 1950 nor the 1954.
