I'm wanting to perform a Cummins 4BT swap into my 02 F150. The truck currently has the M5R2 5-speed transmission. I was planning on putting in an aftermarket towing clutch (OE barely works for me as it is and I'm on my second one at only 125K miles). My big issue is although I may be loosing 50 hp, I will be gaining 120 lb-ft of torque compared to what my 4.2 puts out. Little more simple tuning on the engine and I could get it close to 200 hp and 430 ft-lb. I've heard of guys running 600 hp T-birds on these things. Just how durable are they? The only issue I have with my current transmission is that the 4th gear synchro is going out (that's what double clutching is for). I hear they can out perform T4 and T5's but does anyone know what Mazda actually has the transmissions rated for?

 

It will hold the power and torque I know somebody that has a 68 mustang with heads cam and all the bells and whistles.. And for some reason picked that trans.. There cheaper and easier to come by but shift way slower than a t5. And btw that will be sick cause the 4bt is god

 

Yea, I'm tired of dealing with PCM's and there aren't any rules when it comes to diesel in Texas. I was actually debating maybe competing against stock class diesels in pulls, especially since I am debating starting a pull team at Texas Tech. My father has an 06 6BT ISB and he gets 29 mpg on the highway with his MegaCab. I just really want to find the limit of the transmission, that way I know what I have to work with when it comes to moding the engine. I know they don't make the shift kit for these things anymore, but it would be nice to see if I couldn't mess with the shift forks to turn it into a dog legged transmission.