Ok heres the scoop. I have a 65 M20, and I'm a little concerned it'll blow chunks behind my 430. The 430 is warmed up signifigantly. Probably an honest low 12 second ride. How will the M20 hold up to it??? If any other of the 4 gear guys want to post their combos, along with ET guesses, It'd be appreciated... Thanks Joe :3gears: :3gears:
I have the same one and it has a smaller input shaft than the later ones that were redesigned. Will it last? I was told if you dont race it all the time it should.
4 speed I have run 12.60 @111 with my original Muncie and havent had any real issues with it...I even had slicks on it and it held up. Last year i bought one of the Muncie Super cases from www.5speeds.com, along with the new input shaft/ counter shaft/1st gear and rebuild kit. My motor made 520hp/550 ft lb Tq and I have thrashed it pretty hard :3gears: .
m20 the m20 and m21 are the same except the gear ratios considering that the m20 came in everything from 283 ss cars to 428 pontiacs and in all weights of cars from the a body to the b body you should have no problems if all is well inside and your arm to foot co-ordination is up to snuff! also dont even consider using the stock shifter they are very flexible if dragging and street I would recommend the hurst super shifter 3 but it does take floor mods the comp plus would be a good second choice good luck :3gears:
My cousin has a 400 powered 65 GTO, never had a problem with it till he put slicks on it. Its a 13 second car w/slicks(launches at 4000 RPM) and he has broke 3 of them internally and 1 externally. He broke the case(bolt eyelet for bellhousing) cause the motor would lean when he stomped on it. I think he would have less problem if he launched at a lower RPM or took the slicks off. Food for thought, Dave
i JUST got off the phone with richmond gear . the tech guy said that those trans ( m20 and m21 and their t-10 i was asking about ) were fine behind everything back then because of the limitations to traction - skinny tires and "guesswork" suspension tuning . now with slicks and sticky street tires and numerous good suspension mods available those same trans are alot closer to their limits than before . no problem for a resto/cruiser - but with some serious power - even small block power - and especially with the advent of power adders lately - the trans is 50/50 . not what i wanted to know - i was hoping that richmond gear made some strength improvements to ther new t-10's but he stated that they are basically just as they were 35-40 years ago just new . he said that the basic muncies and the t-10's are almost identical in strength . he of course recommended the five speed as that would up the torque rating by about 100 , 375 to about 475 i think he said , but that is about $500-$800 more when you add in the other slight mods needed . del
check out www.m-22.com they build a super duty M-22 that will handle the torque and traction! there in Peoria, IL and Cape coral, FL
Keep in mind that thegearing is must different between a M-20 and a 21/22. You will need to run a steeper gear with a 21. As for strength and reliability, check out the site Scott mentioned. The supercase and iron mid plate are the way to go. The weakest part of the muncie is the case, and even the 22 stil has the same case. Most failures are caused by the case flexing.
