The Supercar Registry - Unrestored 67 Impala SS427

I noticed the trans too. I wonder if they have a POP for it? Would be interesting to see what trans date is on it.

Also noticed an Impala SS emblem on the right corner of the decklid. That is not correct for an SS427, is it?

On the trans, probably not applicable to this car, but I will share a story on why not to automatically assume that a P0### Muncie stamp can't have come in a 67 model year car.

I inspected a very original 10C built survivor 67 Chevelle SS convertible that had a 66-style Muncie date stamp, P0412. It also had the original part number tag 3890534 on it, which is the 66 M20 with the speedo drive gear for a 3.55 or lower rear axle (this car did have a 3.55 posi). So the spread between trans and car was 6 months. So I said, no bueno!

But then I looked at the POP and it matched the trans. And the POP was definitely real (had some details that none of the repoppers get right for a car from that particular plant).

So I went back under the car with the scope, and after removing a half pound of crud I found the partial VIN stamp on top of the main case, matching the car. All fonts and the format were correct for that plant at that time. And there was no question that the trans had not been out of the car in many decades, if ever.

So I concluded that this was a left over unused 66 3890534 M20 for a low geared car, that the assembly plant finally got around to using on this car. Easy to imagine that happening, because demand for an M20 with a low geared rear axle was presumably lower than M21 demand in that scenario. Also, in the 66 model year, if the "4 Speed" box was checked on the order form, if your big block car had a 3.55 or lower gear (or late in the year, if it was an L78 regardless of the axle ratio), then you got a M21 whether you asked for it or not, UNLESS the salesman specifically put instructions to install an M20 down in one of the blank "Special Instructions" boxes.

So between the lack of demand, and the default "4 speed" trans order rules and the unlikelihood of a large number of salesmen knowing there was any need to override them, there probably weren't very many 66 orders coming in to the assembly plants for cars that needed a 3890534 M20 trans. So some straggling left overs seem very possible.

All that changed with the 67 order form which had different boxes to check for "4 Speed Wide Range" or "4 Speed Close Ratio".

Since this SS427 has a 3.31 rear axle code, all the above probably has nothing at all to do with this car. But I would still love to know if this car has its partial VIN number on the case!