Fortunate Son

Greetings all,

I recently purchased a very nice, numbers matching '67 442. Original 400 with a 3-speed (Toploader I assume).

I want to change the trans to a 4-speed and want to make sure I'm looking for the right gearbox. Planning on an M21. I think it's an HF code case stamp. What else (numbers?) do I need to know? I'd look for the codes myself, but the car hasn't been delivered yet.

Also, what modifications will the drive shaft need in order to fit the 4-speed?

Thanks in advance!


Fortunate Son
'67 442

redoldsman

On a numbers matching car, there is no way I would change it. The 3-speed is somewhat unique. It might not be as much fun as a 4-speed but I would leave it. Of course it is your car and you should do what you want. It will be interesting to see what others say. Enjoy you car and welcome to this site. You need to post some pictures because we love pictures on here.

Oldsmaniac

Well a floor shifted 3 speed would be pretty easy to change to a 4 speed if that is what you want. You will need a different yoke on the driveshaft I have been told and a 4spd shifter. I cant think of anything else really as long as trans spline count is the same for the clutch disc. Just save the original parts.

Fortunate Son

I would be keeping the 3-speed, and would probably change back if/when I were to ever sell the car. The 4-speed is completely a me thing.
I don't plan on doing anything to the car that can't be fairly easily undone.

Once the car is delivered, I'll get some pictures up. I have a few (bad) cell phone pics but they don't do the car justice.

Thank very much for the warm welcome. I'm looking forward to learning a lot here. While I'm not new to old hotrods, I am new to Oldsmobiles and 442's.

Thanks again!


Fortunate Son
'67 442

jaunty75

Do you have the car's protect-o-plate? Without that, as I've seen mentioned on here numerous times by Joe Padavano, it's not possible to prove for a '67 or earlier Oldsmobile that the engine is original to the car.

The concept of "numbers matching" didn't come into play until the '68 model year as that was when Olds actually started stamping a VIN derivative on the engine and transmission. So all you can really verify for a '67 and earlier car is that the date code on the engine and transmission are consistent with the build date of the car itself.

Obviously if the engine was built after the car was assembled, it can't be the original engine. What you're looking for is a date-built code on the engine a few days or a week or so earlier than the date-assembled code on the car's cowl tag.

Of course, having a date-consistent engine and transmission doesn't guarantee that they're original as many thousands of engines and transmissions were built in the days and weeks prior to the assembly of any particular car, so any number of engines and transmissions could be date-consistent.

The bottom line is that there is no way to 100% prove, by looking at the car itself, that any particular engine is original to any particular pre-1968 Oldsmobile.

Unless you have the protect-o-plate, which I believe does have the engine number on it as well as the VIN of the car. But protect-o-plates are not attached to a car and are often lost after so many years as they were just part of what came in the car's glovebox.

oldcutlass

Welcome, looking forward to pictures.


Although I don't know whether you'll need a new yoke or not. And I don't know if the clutch plate is the same, but the swap itself is probably as simple as just the trans and shifter. It's also, like you said easy to go back. I wouldn't hesitate to do it.

Fortunate Son

Thanks to all for the information.
I'll post pics as promised once the car is delivered. We have cold and snow here, so it could be awhile.