[cortcomp]

"Doing some research and I was actually quite surprised no one has ever done this for the Chevy 4 speeds (m20, m21, etc). It's a no-brainer - creating proper OD internal gearsets that is - and considering there are a million more potential GM customers than Mopar customers - I'm very surprised some snazzy business minded folk within the GM community hasn't done it."

I don't have any links, but that for sure has been done with muncie trans by at least one but i think several companies. The main problem you get into with all this is cost. Well, two problems, cost and strength. Any time you do OD like you do on the NP440 or muncie conversion, you are transferring power differently through the trans than say a 5 speed with a planetary setup. It creates the issue of wallowing out or thrust wear on one of the shafts, when you put lots of power to it AND you have traction. In my truck, the 327 will be stock and not have power. In my t-37, i have power but street tires so it doesn't really hook up (and i'm a cruiser anyways, bad a$$ as i pretend to be). So, you end up with a transmission that has wider ratios than a 5 speed, the linkage can by annoying to adjust and maintain, and even when you get it perfect, isn't quite as amazing as a trans where the shifter connects right inside the top. Lastly, to do the muncie conversion, it was like a grand. Then you have a grand to get a muncie in great condition. For that price you can get a nice 5 speed setup.

A lot of guys live gear vendors OD unit and that's nice but it's more work and all that and i prefer an all in one average setup.
There are really two ways to go with these projects in my book, IF YOU ARE GOING TO DROP LIKE 2K, and if you are making decent power. (this doesn't apply to my A-body, because to look and seem normal it needs a side loader and the NP440 is great for a bodies with big torque in my opinion, because they look right and most factory parts fit them, hurst shifters, etc.)

Either get one of those 5 speeds that 5th is 1:1 and you pick a high gear out back like 2.74, which makes your RPMS like you have OD but you have 5 gears to tear it up with so you get the acceleration of having 3.73s, or get a T5 or tremec or something 5 speed that has OD in it. For the money you'd put in a muncie conversion, you have a transmission you're afraid to lean on because you might break it . On the T5/tremec.etc parts are just around. On the NP 440 you can get gears and parts and sleeve that wallowed out case problem and rebuild.

So for me, stick shift and OD being the project:

1K and under: NP440 hands down. Freshen it up, get a new shifter and make your shift rods nice and smooth and no slop, and you'll love it.

Spending over 1k?: Go T5 or something top loader and be done with it.