Auto to 4 speed conversion question

[marcar1993]

I have a 1987 Cutlass Supreme with a 3 speed auto trans with a column shift. I want to put a 4 speed in but I don't know what needs to be modified. Will I have to get a new column, probably. Anyone know where to get one? I also want to know If the shifter will fit, I have a bench seat and I would prefer to leave it that way.

[joe_padavano]

Originally Posted by marcar1993

I have a 1987 Cutlass Supreme with a 3 speed auto trans with a column shift. I want to put a 4 speed in but I don't know what needs to be modified. Will I have to get a new column, probably. Anyone know where to get one? I also want to know If the shifter will fit, I have a bench seat and I would prefer to leave it that way.

Are you talking about installing a manual trans or a 4 speed automatic (200-4R, for example)? Which engine do you have, 307 or V6?

If you're talking about putting a manual trans behind the 307, be aware that Oldsmobile usually did not machine the crank for the pilot bearing if the engine was originally bolted to an automatic. You can either disassemble the engine and have the crank machined or you can get a conversion bearing that fits into the torque converter pilot in the crank and acts as a pilot bearing for the manual trans. The only problem is that you need to trim the tip of the input shaft on the trans.

Of course, you'll need the G-body clutch pedal and linkage. These parts are available as reproductions. Monte Carlo/Chevelle parts fit the Cutlass.

[marcar1993]

I am talking about a 307. I want to bolt a Richmond t-10 to it.

What do you mean by trimming the input shaft. How much, and how precise do I have to be?

[joe_padavano]

Originally Posted by marcar1993

I am talking about a 307. I want to bolt a Richmond t-10 to it.

What do you mean by trimming the input shaft. How much, and how precise do I have to be?

Since the recess in the end of the crank is not drilled deeply enough, the tip of the input shaft that would normally sit in the pilot bearing will botton on the crank. The conversion bearing sits in the torque converter pilot recess and supports the input shaft of the manual trans but you still have this bottoming problem. The instructions that come with the bearing will tell you how much. I seem to recall it's around 1/2" or 3/4". It is not necessary to be precise. You can do it with a hacksaw or cutoff wheel. Just be sure to deburr the edges.

[marcar1993]

Do you know if the shifter will hit the dashboard or the seat?
I have a bench seat and I don't want to go with bucket seats.