Well I guess it is up to our new friend from the UK to send a picture or give more details about the engine. The only picture of the engine in the "Moter's Manual" shows a very primitive single carb on the middle of a long intake manifold that stretches across the side of the block with a similar long exhaust manifold with a center exit and bolted to the bottom of the intake manifold. Perhaps it was the combination of a world-wide Depression followed by WWII but it is amazing looking at the engines of the time from 1935-1951 how little they changed and how primitive the side valve engines were as well as how many companies stayed with that design. The OHV Chevie six looks downright modern compared to the many flathead engines and the only hint of present design shows up in the 1949 Cadillac 331 OHV V8 and that was rated at only 160 HP @3800 rpm. For the sake of homespun history the term "Fordillac" preceded "It's a Hemi" for automotive awe in the early 1950s. Looking at the Motor's picture of the Pontiac 8-cyl, it might not be hard to fabricate a header or split headers that would surely flow better than the stock manifold. That would be a way to improve performance without a turbo. But even with a turbo some plumbing would be necessary to adapt the exhaust flow to the turbo. Just for fun, and recalling pictures of Smokey Yunick leaning over a Hudson six, perhaps the ultimate six of that era was the 308 cu. in. side valve Hudson Hornet rated at 145 H.P. @3800 rpm (equals about 200 ft. lbs. at 3800 rpm). If the Pontiac is to be rebuilt for performance perhaps the lost art of relieving the top of the block might help, although I suspect that is very difficult to keep all the cylinders equal. Maybe with modern milling equipment that could be done in a reproducible way across all the cylinders but that sounds expensive.

Don Shillady
Retired Scientist/teen rodder