Quote:
Originally Posted by geeteeohguy
Car is bagged with a '57 engine. The bagged/wheels ruin it for me. The '56 engine was a 316 CID, not a 317 or 347. Had a friend recently try to swap a '73 Pontiac 350 into a '56 Safari and the 350 would not physically fit between the A arms and frame. It was too wide. Blew our minds as we thought all Ponchos 287--455 were dimensionally the same.
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56 engine is 316.6 cubic inches, rounded up it is 317. 350, is actually 354 cubic inches, and 1963 326, is actually 336 cubic inches, (3.781 bore) same as the Pontiacs that went into the early GMCs. In 64 the bore was downsized (3.718) and was closer to the advertised displacement.
In early articles, the 56 engine were actually referred to as a 316.6 displacement. Pontiacs own service bulletin (Pontiac Service Craftsman) also referred to the engine as 316.6 displacement engine. Back then they referred more to HP ratings, rather than cubic inch displacements. The top of the line 2, 4 bbl 1956 engine was referred to as the 285 HP engine, by Pontiac in their own newsletter in 1956.
I would guess that the reason the late model engine was wider was because the exhaust manifolds were much smaller in diameter in 1956. As the displacement increased. so did the diameter of the log manifolds. Also the steering box placement (rear steer) limited the width of the engine to fit in the cramped space of the 56 chassis. There are 55-57 cars with late model V8s installed, so there has to be some way to shoehorn the late engines into the early chassis.
Many publications list the displacement as 316/317, so take your pick.