[David_Hayward (RIP)]

The GMC 248 cu in unit was produced in Canada from August 1940 for about a year in Walkerville, though all others were imported from Pontiac, MI. It was used throughout the war in GMC and some Maple Leafs. This is an extract from one of my books:

'In fact, civilian production was being discussed as early as March 1945 in THE WAR-CRAFTSMAN with a neat diagram in their March issue to remind General Motors of Canada workers how the system ran in peacetime from Dealer orders to delivery. Re-tooling was undertaken to produce new motors for the peacetime market. The 1946 2-Ton Chevrolet trucks used a new re-cast version of the 216.5 motor, to create a more-powerful 235.5 cu. in “six” used in various Chevrolet Trucks up until 1962, and as mentioned above, in higher-compression form with slight improvements, in the “small” Canadian Pontiacs until 1962, thus endowing the Pontiacs more power than their Chevrolet “sisters”. This new motor was a re-stroked version of the previous 224 in. six as used in Pontiac cars, 1937 to 1941, Maple leaf Trucks and G.M.C.’s, which now measured 3 9/16 x 3 15/16” bore / stroke. G.M.C. and Maple Leaf used either the new 235.5 Chevrolet “six” or the G.M.C. 248.4 “six” in various models at least until 1950. Pontiac Sedan deliveries sold ostensibly by G.M.C. Dealers as “G.M.C.’s” used the 235 in. six. Canadian G.M.C.’s also used the Chevrolet 216.5 cu. in. “six” from 1946, with some versions using the new 235.5 Chevrolet “six”, the G.M.C. 248.4 “six” until 1948 when they added new 269.5 and 308.2 cu. in. motors, and a new Detroit Diesel Diesel “six” of 425.4 cu. ins., depending on normal or forward-control Cab-over-motor models'. The 248 was rated at 33.19 hp...the engine debuted in 1940 and were serialled # G-1001 and up 3 9/16 x 3 12/16 in Bore & Stroke, and was the basic GMC engine before the 270. So, because the 248 originally went in where the 216 did, it should fit straight in. The other queries I'll sort out in a moment my time.