3 spd to 4 spd?

[turbomopar]

I bought a wreked parts car it was a 318 3speed. I would like to put in my 73 duster. I was wondering if I found a 4 speed if it would fit the 3 speed bellhousing?

 

['64 Cuda]

It might. The 3 & 4 speed transmissions bolt up to the bellhousings with different bolt patterns. Some bellhousings are drilled with both bolt patterns. You also need to be sure that the register (the large diameter hole where the trans fits into the bellhousing) is correct for the transmission. Check out this link. It's slant six stuff but the transmission info is pretty much the same no matter which engine you have.

http://www.slantsix.org/articles/4-speeds/ODA833fourspeed1.htm

 

[green1]

I know a 70 is tapped for both.

 

[scuba0331]

my 74 Duster had a 318 3-speed that I changed over to a 360 4 speed and I used the same bellhousing.

 

[72bluNblu]

I bought a wreked parts car it was a 318 3speed. I would like to put in my 73 duster. I was wondering if I found a 4 speed if it would fit the 3 speed bellhousing?

As others have mentioned already it should. Both bolt patterns should be there. Biggest thing would be making sure the front bearing retainer on the 4 speed is the same size as the 3 speed, since the 4 speeds have several different sizes depending on what year they are.

You'll also need a new shifter, shift rods, and probably a driveshaft (or have the old one sized).