M5R2 Questions

SloMo228

Registered User
I'm considering a 5-speed swap in my 94 4.6 LX. I already know the M5R2 will not bolt up to the 4.6, but I'm also considering a engine swap to a 351C. I've been told that the M5R2 will bolt up to a 5.0L engine, and since the 351 has the same bellhousing pattern, it will too. (Since I live in MI with no emissions testing, this is all fine and dandy :) ). What I want to know is, how strong is the M5R2? I'm building the engine for around 300RWHP and 300+ (as high as I can get it) RWTQ. Will the M5R2 be able to stand up to that, reliably? I know there's a lot of modded SC's on here pushing that much power through the 5-speed, have you had any problems? Have you had to use a different clutch? Also, are there any years I should try to get that are stronger than others? And, how much should I be looking to spend for an M5R2. I'll more than likely be rebuilding it, unless I find one from a super low-mileage SC. And if I find that, I'd probably feel too bad about tearing it apart to take that trans. Well, thanks for any info you can give me!

-Steve
 
The M5R2 will indeed stand up to 300 rwhp with no problem but I do not recommend using it. The fiber type synchronizer blockers that allow speed shifting are becoming rare since they are out of production. The solid brass blockers that are used in the truck version are plentyful but tend to grind on speed shifting although they are fine for everyday driving. I go thru a set of fiber blockers every 2 years in my drag racer running about 15 weekends per year but I have a spare tranny and enough blockers to last me 10 years. The brass blockers lasted a year with speed shifting, chewed the outer edge teeth right off of them. It is also a bit notchy and awkward to shift without a Ripper. They are notorious for it. I'd recommend either a Tremec or maybe this new T5 that uses 50% larger gears than the World Class T5.
 
I've always heard that the T5 is weaker than the M5R2. The notchy shift doesn't bother me much, the only 5-speed I've ever owned was a Geo Tracker...not the world's best as far as shifter feel is concerned. Is there any possibility of having special blockers made from some high-strength/durable material? Let me rephrase that. Of course it's possible, but could it be done in the average machine shop?
 
The T-5s from mustangs and etc are weaker... A good aftermarket T-5 (Tremec for example) would be a bit tougher. I still want to see a T-56 in a bird... ;) I want to try it on mine but thats a ways off still.
 
So what is the TQ limit for an M5R2? The T5 can handle around 320 ft-lbs, but I'd reeeaaaallly like more than that.
 
Sure, there are T5's that can handle whatever you throw at them, but those are generally out of the price range of the average guy, which puts them well out of my range. :) I don't drag race much, so I think I might just go with the M5R2 for simplicity.
 
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