Whats the freakn difference? I read somewhere that the mn12 is equal to having 3:90s in a c5.

Can you make a mn6 a mn12?

If it is like having 3:90s why aren’t more people doing this instead of gears? Is it just more expensive?

What parts would I need to change over my mn6 to the zo6
tranny?

 

Use the search feature....you will find quite a bit of info on this topic. Like most things in life the MN6/MN12 debate is a compromise. The MN12 has much lower ratio's in the first two gears but also comes with the penalty of a larger RPM drop between them, especially the 3-4 shift, putting your engine farther out of the powerband during the run. Fourth gear in both is one to one....essentially the MN12 is a wide ratio box and the MN6 is a close ratio box. For pure drag race, the better set-up in my opinion is a low gear and the tight ratio gearbox (the MN6)....less RPM drop between the gears and more average power over the duration of the run....BUT, some of the MN12 guys with a steep rear end gears (3.90/4.10) have cut some pretty killer ET's, and very impressive 60 foots due to such a low gear ratio in first (J-Rod comes to mind here).

Its an on going debate and I think its more of a personal decision than much else...there isn't clearcut eveidence that either of them is the ultimate winner.....I think its a very application sensitive kind of choice. IF there were a lower ratio available (like a 4.30 or a 4.56) the MN6 would be a no brainer in a drag race.....good 1st gear TQ multiplication and less drop between gears rowing it down the track.

Hope this helps...
Tony M.

EDIT: Patches...GREAT info below

 

The Z06 uses a specific "M12" version of this transmission having higher ratios in the first three gears (2.97/2.07/1.43 vs 2.66/1.78/1.30) which makes the M12 a wider-ratio trans than the MN6 used in Coupes and Convertibles. Although this does simulate a 3.90 rear gear setup in an MN6, the wider gear spacing isn't as good a fit to an LS1 as it is to an LS6 torque band.

It's cheaper to swap diff than the tranny. Plus, the MN6 tranny is rated 50 lbs. ft. higher than the M12. Here's a comparison of gears and diffs of the two trannies.

 

Thanks guys, the info is great here!