4 speed Muncie with 3 speed bell housing

[350pwr]

Good afternoon all,
I swapped my old 3 on the tree for a 4 speed Muncie, and I kept the 3 speed bell housing. Unfortunately, I noticed a gap between the gearbox and housing. Muncie retainer is 4.125 inches wide, the bell housing is 5.6875 inches wide. Should I insert a spacer I just received from summit, or will the setup be ok?
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[kwmech]

spacer should be used to help center the trans into the back of the crankshaft.

[Grumpy old man]

The 67 3 speed bell housing is the right size to fit the Muncie trans without a spacer , The 68 up need a spacer . Muncies are famous for cracking the mount ears off if not supported right . What shifter are you going to use ? Hurst makes one to fit the 67-72 Chevy trucks . I also added a tail shaft mount , I wasn't happy having the trans just hanging off the bell housing .

[350pwr]

I am running a Hurst shifter, and I also have a tail shaft mount as well. My bell housing has a larger bore than the Muncie, so it must be a 68 and up bell housing.

[Tator]

Advanced Adapters has a ring to fit. Just used one and it fit great.

https://www.advanceadapters.com/5403

*edit, due to not reading*

Yes, you need to support the input bearing retainer, do not rely on the 4 bolts to keep the trans from moving around. That is a good way to bust an ear or case.

[68 C10 Driver]

Interesting post, I am installing a Muncie M20 in my truck as well. I purchased an aluminum bellhousing and will install a transmission mount under the rear of the M20. I installed a Hurst Competition Plus shifter and got the shifter made for the bench seats. I also bought a new reverse lamp switch so the back-up lights work as they should.

It is funny how very few posts there are regarding the use of Muncies in our trucks...I guess everyone is after the 5 and 6 speed trannies or overdrives. My intent is to build something as it would have back in 68/69 with as much period correct items as possible.

Great post, thanks!

[zicc1835]

Originally Posted by 68 C10 Driver

Interesting post, I am installing a Muncie M20 in my truck as well. I purchased an aluminum bellhousing and will install a transmission mount under the rear of the M20. I installed a Hurst Competition Plus shifter and got the shifter made for the bench seats. I also bought a new reverse lamp switch so the back-up lights work as they should.

It is funny how very few posts there are regarding the use of Muncies in our trucks...I guess everyone is after the 5 and 6 speed trannies or overdrives. My intent is to build something as it would have back in 68/69 with as much period correct items as possible.

Great post, thanks!

have that set up im my step side was a in line6 3 on tree 1 wheel peel now date correct truck 327 mild cam m-20 373 posi ( currently under renovations body work paint heads redone roller rockers main
bearings etc.) love the 4 speed
https://studio.youtube.com/video/_r5WjTNNUcc/edit

[HalfBrit]

Hey Grumpy, wasn't aware there were compatibility issues with the Muncie. I've owned my '70 C10 since 1990 (base/307/3spd). Around '95 I swapped the motor and trans. for a 350/M21 combo. I didn't have any fitment issues at that time, with the bell housing. Maybe I got lucky?

[Grumpy old man]

Originally Posted by HalfBrit

Hey Grumpy, wasn't aware there were compatibility issues with the Muncie. I've owned my '70 C10 since 1990 (base/307/3spd). Around '95 I swapped the motor and trans. for a 350/M21 combo. I didn't have any fitment issues at that time, with the bell housing. Maybe I got lucky?

This thread shows how I installed mine .

https://www.67-72chevytrucks.com/vbo...d.php?t=814944

This truck was originally a 67 292/3 speed short bed , Project creep lead it to 350 4 bolt with the M22 and a 3.73 posi with 29" tires 3.5/5" static drop and front disc conversion a rear mounted tank and all stainless lines with a wood bed . I swapped out the 6 manual trans cross member mount for the V8 cross member so the engine/ bell housing would be in the stock V8 position , Since I already had a few 67 bell housings that fit the Muncie 22 input it was a no brainer for a period shop truck build . I've done the math it all works .

[Accelo]

Decades ago I installed a stock 302 ci SBC in a Camaro I had with 308 gears.
I pulled the motor and installed it in a Corvette with 3:73 gears. Nobody would believe it was the same motor as it ran so much better with the lower gears. The 4 speed in the Camaro would do almost 60mph in first!
3:08 gears are fine but use them with a large motor with lots of torque and be happy.

[geezer#99]

A 3.08 gear with a 2.20 first gear isn’t the best combo.
It’s a long ways from the ideal 10 to 1 overall first gear ratio.
3.73 is better.
4.10 better yet.
4.56 the best.
The last two aren’t ideal for all around driving so using a higher first gear like an m20 2.52 gear helps with the 3.73.
Auto gear has a m22z with a taller 2.98 first. Would work with a 3.08 or maybe better a 3.55.