anyone ever put a muncie 4 speed in

[mrgoodwrench_420]

i have a 68 short bed with 350 and am trying to put a muncie 4 speed in does it fit can i use a auto trans cross member do i have to remove the old 3speed i6 cross member and does any one have any for sale

[sweet n rare67]

I am still in progress the biggest problem so far...is getting a shifter however I have a plan...I will have to get some pics for you guys to look at and let me know what you think....Too answer some of your questions....

You can mount a M21 to a small block on I6 engine towers, and use the original crossmembers..If you are lookin for something a little stronger...You can also mount the small block on v8 towers and install an auto crossmember...I am currently moving mine forward, installing an aftermarket tubular one from CPP...As far as removing the original bellhousing crossmember I have not decided what i am goin to do with it..

-Jake

[FRENCHBLUE72]

I had a muncie in my 72 used the stock crossmember and cut otu the bellhousing crossmember. I used a lakewood scattershield to mount it up to the motor and used the stock clutch linkage.

[Bowtie67]

If you have the original bellhousing and your truck was a standard you could use the same mounts, you can also use an auto crossmemeber but I am not sure if bolt holes will line up. If your previous trans was a 3speed the bell housing center hole is smaller and a 4speed wont fit unless some previous owner had had replaced the bell housing at some point. You can have the hole machined bigger to accept the 4speed bearing support. Also depending on what trans you had in there you will most likely need to also replace the clutch, most of the muncies had fine tooth input shaft as well as a fine tooth output shaft, most 3 spd & and truck had course splines. Three speeds and the truck 4speed had a longer driveshaft and that may require shorting as well.

Just a note I have the bell Housing you need as well as bellhousing mounts and an automatic trans cross member. there are two Bell Housings here
http://67-72chevytrucks.com/vboard/s...d.php?t=188431 and I didnt list the trans cross member on that post because I wasnt sure if I was going to need it, I also have flywheels and clutches listed there as well that are in excellant shape.

[davidh]

[QUOTE=sweet n rare67]I am still in progress the biggest problem so far...is getting a shifter however I have a plan...I will have to get some pics for you guys to look at and let me know what you think....Too answer some of your questions....


I saw in classic trucks where a company that makes shifters for car trannys for trucks. It puts the shifter in the middle of the trans tunnel. I can't remember their name right off.

[OleBlue69]

I have a M-20 in mine with an 11" car bellhousing and hurst shifter and linkage - working out great. Here's the part number for the shifter at summit: HUU-3910002. Mine had an automatic. I cut a hole in the floor for the shifter and used the automatic crossmemeber. Good luck.

[crazy longhorn]

The M 20/21 are a pretty nice bolt in with the proper pcs. On the bell housing.......its a yr specific deal. The 67 & older truck bells have a 4 .683 centerhole, same as the cars& the 68 on truck bells have a 5.126 centerhole(this does not matter if it was 3 or 4spd truck trans). the early 3 spd trans(ID by a 4 bolt sidecover) were a shortie. 68 or 69, the saginaw 3 spd became standard equipment in the 3 spd trucks(ID by a 7 bolt sidecover). This trans was also a fully syncronized unit, & shared the same lenght with the M20/21, as well as the slipyolk spline. Some of these did have a 26 spline input shaft vs the 10 spline truck unit. The M22, refered to as the "rockcrusher" was the badboy with the lower angle on the gears(nice gear whine)! This trans was also the same lenght, but had the 26 spline input, & a larger (400turbo sized) output shaft/slipyolk. It been several yrs since I played with the old Muncies, but Im sure someone has a site with specs. I have heard that the Hurst shifter for a 57 belair, will fit the bench seat in the truck(cant confirm this tho). I will say that things will be tight with any shifter combo that has bench seat , & is in I6 position on the eng/trans. I run buckets in my swaps, & found that a universal Hurst Indy or superspeedway shifter worked fine with a straight stick handle. The only drawback on the 21/22 was the very tall 1st gear (2.20 to 1), as it really compomised the ratio on takeoff(especially with a heavy load). Once you got rolling the close ratio gears really felt good tho! Best of luck, L

[special-K]

I bolted on M21 into a 3spd`70 C/10 one day using only existing parts on truck.