Why did Pontiac get overhead valves so late?

[Tom Beggan]

Just curious, but it strikes me that my Pontiacs (a 1932 6-cylinder and a 1934 8-cylinder) came without overhead valves, while other cars, like Chevy and Buick, etc... already had overhead valves as far back as the late twenties.

The Buick makes sense I suppose, but if Pontiac was positioned as a "step up" from Chevy, why would Chevys come with a more advanced engine? I've always wondered about that. And I'm betting there's an interesting story behind it too.

Also, is there any advantage/disadvantage in overhead designs vs those they replaced?

[pontiac1953]

hi tom, pontiac was the first corporate type car, chevy would share body parts with the oakland pontiac, and oldsmobile was helping with the engine design. i believe that when pontiac started, chevy only had a four cylinder engine, pontiac didn't go down to a four cylinder engine untill the 1961 tempest. the flathead design limited the engine output (horsepower), the overhead valve design is more efficent, allowed higher compression ratio's. keep in mind that the pontiac straight eight was GM's lowest priced eight cylinder car, if buick and oldsmobile hadn't gone to GM's board of directors in 1952, crying that they would lose a good portion of their customers, if pontiac was allowed to introduce the new overhead valve 287 V8 engine in 1953. cadillac and oldsmobile in 1949, brought out new overhead valve engines, buick had the 322 nailhead V8 ready for the roadmaster and super series models, leaving the cheaper buick special to have the 263 overhead valve straight one more year. pontiac had started desiging a 269 flathead V8 in 1946, in 1949 pontiac took an olds 1949 303 rocket V8, downsized it to a 270, ran it along side pontiac's 269 engine, and the writing was on the walls, the olds overhead design made more horsepower, got better fuel mileage, operated cooler, allowed higher compression ratio's if required. so pontiac started over, with a clean sheet of paper, and designed the 287 strato streak overhead valve V8. in 1952, pontiac had 23 production prototypes of the 53 pontiac, built with the 287 V8, going thru testing on pontiac's and GM's proving grounds. i am changing my 1953 pontiac custom catalina to also have the 287 strato streak V8, as a tribute to the 23 prototypes that never made it to the showroom floor. charles coker, 1953 pontiac tech advisor, poci.

[Tom Beggan]

Thanks Charles, I figured there'd be an interesting story in there somewhere. I tend to be a fan of the flathead because it looks so different. I don't mind telling you I'd certainly appreciate a few more rev's (for highway travel), but that's the way they built them. take care, Tom

[61-63]

Thanks Charles that information was very interesting. I am an early 60s Pontiac fan but the background on all matters Pontiac are informative.

[kencary]

Good summary.

I would also add that in the early '50s, quiteness and smoothness was given a premium over power. Prior to the horsepower race of the mid 50's, the flathead was, and still is smoother and quieter than an OHV V8.

Some of these old flatheads would idle around 400RPM. Also the side valve engine buried the lifters and cam in the cast iron block which added to the quiet sound of the engine.
As a "sensible" family car, some did not want to mess with success-- 1950 was a banner sales year for Pontiac. Once car makers touted their horsepower as a key marketing element, the game changed and the Flathead was doomed.

When I lift the hood on a flathead Pontiac, the only thing I hear is the fan, water pump and generator. This much more civilized than the clatter of my '68 Vette 427 shaking away under the hood.

The flathead is even quiter and smoother than the refined DOHC V8 in my Landrover.

Personally, this is a big reason why I wanted a pre-55 Pontiac.