Wouldn't it be the best to have a 661 Case with 2.52 or 2.56 1st gear then 2nd at 1.64 and 3rd at 1.28 then 4th 1.00 ? instead of M-20 starting out at 2.20 and so on so the heavy Buick can take off with 3.73 rear end or not. Just wondering what would be the best for strip with 3.73 or 3.90 rear. not sure how tall tires would be, maybe 30" or 31"
Here's my take on this debate, imo close ratio M21 came behind performance cars for a reason and m20's came behind low performance mills for a reason. Now ive never really driven an M20 for any length of time just a month I owned a 70 442 and with an engine of adequate power why would we want to aggravate traction and first gear pull with a short first gear as the m20 and say a 373 ? My pops m22 stock ratio will push your eyes back from a 30 roll , I can see where a wider split would help wgen working with traction limited situations I suppose idk maybe im talking circles ha but im sticking to my guns close ratio ftw
Despite the 3.90 posi in my '64 Impala convertible with a SHP 327, I would really have liked the steeper wide ratio first gear. Unless I got in a race from a rolling start, it was clutch smoke with that land whale. Off the line, those rear gears weren't enough. As mentioned, if I was rolling, it was a rocket. Guess you just have to pick your race style.
I have an m20 with 3.42 rear and I have no issues. Seem powerful to me. Will easily break the wheels loose. But I've not had the chance to drive an m21.
In all fairness, the cam I had was a little peaky for that boat, and I bet it weighed at least 1000 pounds more than a Skylark. I had lost third gear (the guy that originally bought raced it a lot). I put a 3 speed in it with a 2.6x first gear, and it would really launch. Since third and the counter gear were toast, I should have gone ahead and bought the rest of the gears. I didn't keep the three speed in it because of the wider splits. I sold that car over 30 years ago. If we only knew.
What i mean is it would be better to have a lower first gear with less spread between 1st and 2nd like this chart. to keep the reduction the same or close for all gears. IDK[TABLE="width: 100%"] <tbody>[TR] [TD="colspan: 9"]Ratio of drop between gears [/TD] [/TR] [TR] [TD]Transmission [/TD] [TD]1st [/TD] [TD]2nd [/TD] [TD]% Reduction [/TD] [TD]3rd [/TD] [TD]% Reduction [/TD] [TD]4th [/TD] [TD]% Reduction [/TD] [TD]Reverse [/TD] [/TR] [TR] [TD]M20 (63-65) [/TD] [TD]2.56 [/TD] [TD]1.91 [/TD] [TD]25.39% [/TD] [TD]1.48 [/TD] [TD]22.51% [/TD] [TD]1.00 [/TD] [TD]32.43% [/TD] [TD]2.64 [/TD] [/TR] [TR] [TD]M20 (66>) [/TD] [TD]2.52 [/TD] [TD]1.88 [/TD] [TD]25.40% [/TD] [TD]1.46 [/TD] [TD]22.34% [/TD] [TD]1.00 [/TD] [TD]31.51% [/TD] [TD]2.59 [/TD] [/TR] [TR] [TD]M21/M22 [/TD] [TD]2.20 [/TD] [TD]1.64 [/TD] [TD]25.45% [/TD] [TD]1.28 [/TD] [TD]21.95% [/TD] [TD]1.00 [/TD] [TD]21.88% [/TD] [TD]2.26 [/TD] [/TR] </tbody>[/TABLE] If you could put the 2.52 in the M21/22 in place of the 2.20 you could really rip i would think.
It can be done as can an overdriven gear put in 4th call LIBERTY Performance 313 278 4040 , Jim if remember is who you will talk too
I personally like the wide ratio with a BBB because (for my application) you can have a higher (lower numerically) rear end, but that low 1st for nasty hole shots, and the wider spread will drop the rpms down which is where a BBB's torque becomes ideal. The close ratios keeps the rpms up but I feel you lose some torque utilization that way. My m20 is temporary, but is getting replaced with an autogear m22W which is the wide ratio but cut like an m22 gear for strength. In think alit of the close vs wide is personal preference and intended use/driving style though.
Hi, I've had a wide ratio T10 (same as an early M20)for 4 years in a daily driver SBB and enjoy it so much i got a a wide ratio M-20 for my 65 Skylark running a nailhead, I later went to a wide/close ratio Autograph M22W has a slightly different gear spread compared to stock M20 and have no complaints also hasn't broken like 2 other muncies i had Wide ratio seems good for street driven cars close ratio I heard was used to limit tire spin back in the day due to tire technology, also from the factory close ratio gears were 3.55-4:56 vs wide were 3:23-3:55 for the most part which is better suited for a driver but with today's tire technology should work good on the strip Regards,
You could go with a 2nd design ST-10 2.64W or 2.64X... 2.64W------2.64----1.75----1.33----1.00... ratio drops... 34%----24%----25% 2.64X------2.64----1.61----1.23----1.00... ratio drops... 39%----24%----19% I build a lot of these for Vintage Road racing... I could build these with 904 iron main case and iron mid-plate... Last summer built a 2.64W for a customer with a 1969 442 with a very warmed up 455... I had to create a shifter mounting plate and install kit to use the OEM Hurst shifter into the original shifter hole... Hope this helps... Crash
Just throwing it out there. I have seen gear sets for the muncie were first gear is 2.90 or 2.80 or something. With the m22 more straightened gear pattern and you cs5n put it in any muncie case.
My 70 Vette 350/350 hp has 3.70 rear with an M21. It's great for the 1/4 mile but terrible for cruising. The engine tachs 3,500 at 70 mph, I get tired of listening to it. There's almost no difference between 2nd and 3rd gear. I have a 3.08 gear set and the parts to convert to an M20 if I can ever get around to doing it. By the way, you only need to change 2 parts to convert from an M20 to M21, the input and cluster gears. I'm not sure how much power a Saginaw can take, but, you can get them with 2.54, 2.75, 3.11 and 3.50 first gears. Saginaw also made fully synchronized 3 speeds with overdrive and the overdrive unit will also fit on the 4 speed making it an 8 speed. I have the parts to build one for my 65 Special conv.
I don't know how much power a 4 speed Saginaw can take either, but after a few launches with my '69 Camaro (327 with a two barrel at the time), it knocked under load, all kinds of pulling out and looking at parts, replacing some, and finally changing it out with a 4 speed Muncie from a '64 Impala, in '74. No problems after that. I was not savvy enough in '74 to be sure what was wrong, and I had help from my ex-brother-in-law, who was real good at just changing parts until things worked.
I always preferred wide ratio with a low (numerically high) first gear on the strip. Tried close ratio, just didn't like it.
So the high 1st gear would be for spin of clutch and front end lift and body roll. Or the car would run over top rpms in a 6100 rpm BBB before it really got moving ? It is all trial and error i'm sure as to what the car weighs and tires and such and such and so on. like to get it closer in my mind as to what i would like, like.... Autogear 26 32 with iron midplate 2.52 fist 1.64 , 1.28 , 1.00 (With a 3-55 or 3-73 rear...) Its great to get the imput of guys that can run there cars all year or most of it for test and or beating purposes THANX
Message Paul Massiconte, probably butchered his last name he runs his 4speed car hard and has several combos in it, good fella to talk too super helpful
X2. Paul helped point me in the right direction when I first got going on my 4 speed. He's a good dude and very knowledgeable.
