Hi, My Dad has a 40 Pontiac coupe with the original flathead 6 and 3 speed manual transmission. We're thinking about putting in later model Chevy straight 6, either a 250 or a 292. My main concerns at this point are the motor mounts and the bellhousing/transmission. At this point, I don't want to get into swapping in another transmission as well, I'd prefer to use the existing one. I haven't been able to find anything about how to swap the Chevy in, but I'm hoping it's pretty much a straight swap. Does anybody have any experience with something like this, or where I could get motor mount adapters for it? Thanks, Dan
that ****** ain't gonna work, at least not without lots of figuring, fabbin' & money. best to put eng/auto. trans in from same car. a friend put a 250 six & T350 in a 41 Pontiac, said it was pretty straightforward. if you can fab motor mounts, you can fab a ****** mount too. check Ch***is Eng. for mounts. can't remember what rear axle he used.
The stock '40 Pontiac transmission will not easily adapt to the later Chev engine. The Pontiac/Olds/Buick transmissions from the late '30s thru the mid/late '50s have a 'unique' arrangement where they meet the bellhousing. Most manual trannies have a front bearing retainer with a 'snout' that serves as a carrier for the throw out bearing. The BOP trannies do not have this retainer/ TO brg sleeve. The bellhousing has an inserted tube in a small bore in the bellhousing that supports the TO brg. The bellhousing has a machined recess that acts as the trans front bearing retainer when they are bolted together. Further, it requires a gasket between the bell and trans to keep the trans lube from leaking. A major PITA design, especially when it comes to adapting. You would be far better by using a transmission, either stick or automatic, that was originally used with the engine you select.
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