I have 3 mazdas one runs good other 2 for parts the one that runs is a 90 b2200 carb 5 speed standard model, other is a 89 b2000 club cab 5 speed other is the luxury model b2200 carb tilt wheel cruise. but my truck that runs in fith gear at 2500rpm's im only runnin 50. I am wanting to gear it higher which one of thoose trucks might have a higher ratio rear end? any clues would help

 

they are a ford truck with Mazda stickers

 

If the luxury has an auto trans, it should have a lower gear. Autos tend to be geared lower to offset the gas mileage.

 

JimF is 100% wrong, mazda pickup trucks did not become ford rebadges until 1994, you will find almost nothing that will interchange from a ford to a B2200 or B2000 in the United States.

Those of us who actually own the truck in question prefer to swap a transmission from an RX-7 or Miata. I have a miata transmission in mine and love it. The 1st gen B2000 (84 and older) have a 3.308 differential, you should be able to remove the ring and pinion and swap it into your third member.

For U.S. models both the B2200 and B2000s with manual and automatic transmissions used a 3.909 differential, Mazda changed the internal gearing of the automatic to get the desired operating conditions.

The 2wd B2600i uses a 3.73 differential for both manual and automatic trucks however it is the the larger "P" type differential and will not swap into the B2200 unless you swap the entire rear axle. This information is directly from the 1991 B2200/B2600i Factory Manual.