Passion Hemi OD

We installed one of his 4 speed OD (not his new 5 speed) in a 73 Cuda with a 451 big block. Works great and with 3.73 gears the car gets 20 mpg (if you can keep your foot out of it.) You may be lucky and your 3 speed bell housing may have both patterns to bolt in the 4 speed.He is a good guy and easy to deal with and has done many transmissions for us over the last 20 years.
When it comes to 4-5-6 speed OD, our theory was you will run out of road before 5 or 6th gear is needed.Just a thought.