I just picked up a very straight 64 special with the 2bbl 300 and a 3 speed column converted to floor shift. I would like to install either a t-10 4 speed or m-20 and would appreciate thoughts on both. I plan on only mildly beefing up the 300 to a 4bbl and mild cam but would like to have a strong transmission that could handle more horsepower in the future should I decide to go that route. One question I have is if the bellhousing from my stock 3 speed will fit either of these transmissions and are the lengths of the transmissions different. If I am correct these transmissions both have 10 and 27 spline shaft models would this be a direct replacement or are there mods I am unaware of. Additionally would now be the time to upgrade to a 26 and 32 spline m20 or m21? I would prefer a wide ratio transmission for driveability. I have been searching all over this site and am sure the info is here but not in one concise answer particular to my car. Additionally does the 64 Special A body share most of the same drive line/suspension as Chevelles/Malibus/Tempests and other GM A bodys of this year? Thanks Kelly SF Bay Area
Also is installing a transmission hump the way to go or will just cutting the floor suffice (already cut for 3 speed) and I would like to retain the factory bench seat. Thanks again Kelly
The Muncie transmission will be a direct replacement for your 3 speed. The BW T-10 is a good trans but is about 1" longer so you'd have to shorten your driveshaft. It also has a 26 spline input shaft so you'd need a new clutch plate, and the output shaft is a 32 spline so you would need a new yoke. The yoke is also larger on the T-10. In your search for a Muncie, go with an M20. You won't like the close ratio M21 at all unless you have a 3.73 or higher numerical rear gear.
This is probably more of a person preference item. Personally, I like the hump but others just mount the boot to the tunnel. Keep in mind that if you go with the hump you will likely have to replace the carpet so it would be contoured to fit.
Sounds like I'm gonna go with a Muncie m20 wide ratio. I believe its the 325(last digits in the #) model for the main body is that correct? What tail shaft # do I need? Will a corvette m20 fit? Would you all go with the 10/27 spline trans or upgrade to a 26/32 spline taking into account that the clutch disk and yoke will be different? If upgrading what disk diameter/part # should I use? My concern is that I would like a drop in replacement that mates to the buick 300 with no mods Thanks for the quick replies Kelly Anyone got a muncie m20 that would fit for sale?
I'll stick to humpless for easy carpet kit sourcing dont want to order a kit for a 4 speed skylark as an example and get a molded hump when I dont have one. Were all automatics in the 64 year column shift?
#325 would be for a `65. The `66-`67 model years used #010, `68-`69 used #660, and `70-`72 used #661. These numbers apply to all of the Muncie transmssions whether they are M20, M21, or M22. Tailshaft numbers will vary as well, and although there were mechanical variances the transmissions will all have the same external dimensions regardless of whether they came out of a Corvette, Impala, GTO, Buick, etc. Contrary to what many will tell you, there is nothing special about a Corvette transmission in relation to all other models. Some of them will have the speedometer cable on the right, some will be on the left depending on the application. Most common clutches are 10 1/2" or 11". A 10 1/2" will be fine for your application. A Muncie is a good tranmission as is a BW T10, but the Muncie is the bolt in, a T10 is not. Personally, I wouldn't go to the trouble of getting a different yoke and shorten a driveshaft just to have that transmission but that's entirely up to you.
Hi and welcome to the board. The 64-65 Specials and Skylarks orginally came with T-10 four speeds and this might make it easier. The T-10 can handle the 300 with mods. If you are interested in the car looking like a factory 4 speed see this sticky( http://v8buick.com/showthread.php?t=164721) for the run down on all of the factory correct parts. If you decide to run a factory floor hump the factory automatic carpet will normally work as the hump is fairly small. Since all of the four speed cars Im aware of were bucket seat cars im not sure on shifter clearance for a bench seat with the factory Hurst shifter. Im sure you can find a Hurst shifter handle that will clear with some searching but this would force you to use a later style Hurst shifter with the bolt on handle. If you dont care about factory appearance either transmission can be made to work. All 64 automatic cars were column shift only. Being a three speed car orginally saves searching for lots of the difficult parts. You already have the correct flywheel, bellhousing, pedals, etc.
Thanks Mark! Ive found a rebuilt m20 for 600 bucks and a muncie looking top shifter with hurst lower portion and all linkages new for a 64 chevelle with a bench the shifter setup is 400 bucks though anyways for a grand it looks like i will be in good shape.
The 3 speed yoke should work just fine in the M20, and the transmission shaft diameter where it goes into the pilot bushing is 9/16".
The 65-66 Skylark GS used a hump nearly identical to the 64-67 Chevelles. Fits nicely under the regular carpet set for the automatics. It's $40, the boot is $20 and the retaining ring, another $20. A chevelle supplier like Ground Up has it all www.ss396.com A NEW Hurst or repo Muncie shifter will be $400 for the whole kit. A used one...much less! Didn't the Muncies get 1/2" longer and change the output shaft spline count in 1971?
Glad I could help! I regularly hit several Chev and Pontiac resto suppliers at the East coast swap meets.... some of my favorites are Ames Performance ans Performance Years....both Pontiac: http://www.amesperf.com/ http://performanceyears.com/ Performance Years also has a great forum. Hate to say it, but you can find more 64-67 tech info there than here.
