58 Muncie Install Help

[Jason P.]

Hi,

I am hoping someone can help me with what I am wanting to do. I am sure this has been done before.

I am trying to install a 327 engine with a Muncie transmission in my 1958 Corvette. I don't have the original motor and want to try repurpose what I have.


I have read that in order to install a Muncie into a 55-62 Corvette you need to get an adapter plate which was used on 1962 ONLY Corvettes with a 4sp (T-10). Also, it is GREATLY BENEFICIAL to lower the transmission cross member approximately 1in to improve the driveline angle.


I am trying to determine what else I need to do in order to get this drive train setup to work.


Here is what I am working with:

• Bellhousing - GM 3899621 (Would this bellhousing work?)
  • I have the correct flywheel, clutch, and pressure plate to go with the tranny spline and bellhousing
  
  
• GM 3858180 327 Block
• Muncie M20 Transmission
• Clutch fork? Not sure what clutch fork I need to get.
  Should the clutch fork be "matched" up with the bellhousing or the vehicle (I currently don't have a clutch fork and need to know which one to buy)

Also, I purchased what I believe is the correct fan (non-clutch) to go with the 58. When I attach it to the short water pump, it hits the crankshaft pulley. I am thinking I may have the wrong crank pulley.

Corvette Central shows 2 versions for the crank pulley. Which one do I need:

• 301101 - https://www.corvettecentral.com/c1-5...f%3fcount%3d13
• 301105 - https://www.corvettecentral.com/c1-5...f%3fcount%3d13

Here is the water pump pulley I purchased from Corvette Central: 301103 - https://www.corvettecentral.com/c1-5...f%3fcount%3d13

I am guessing that I will also need:

• Harmonic balancer spacer? https://www.corvettecentral.com/c1-5...26years%3d1958
• Water pump pulley reinforcement: https://www.corvettecentral.com/c1-5...f%3fcount%3d18

I know there are a lot of questions here and I hope someone has done this before and can share with me what they had to do in order to get it to work.

Thanks in advance for any and all feedback.

Jason

[Joseph L.]

Re: 58 Muncie Install Help

Hi Jason

For mounting the Hurst Shifter, you will need a Hurst mounting adaptor plate 2223. See the article in the Sept 2023 SoCal newsletter for that information.

Driveline angles are dependent on the configuration of the rear springs. If they are worn, or sag in the front or rear, that will change the pinion angle. You want to match the pinion angle and the transmission output angle (driveline phase angle). Shimming the transmission at the rear crossmember will accomplish that. Measurements with the car sitting on the ground will be needed. See the article in the Sept 2022 SoCal newsletter for that information.

Joe

[Tom P.]

Re: 58 Muncie Install Help

I am quite familiar with installing a Muncie in a 56-62 Corvette.
Here is what you need. It is virtually a pure (well, mostly) plug and play swap.
The pictures below are my 56 with a Muncie, which has been like this for 50yrs and works just fine.
You need a 1962 (ONE YEAR ONLY) rear transmission mount adapter plate. Readily available from all the vendors for about $20.
The transmission cross member needs to be spaced DOWN from the frame X-member. I use 1in square tubing, per the picture. You can use whatever works.
THERE IS NO SUCH THING AS A SHIFTER AVAILABLE FOR A MUNCIE IN A 56-62 MODEL. So, what works, and looks correct, is a Hurst shifter for a 63-65 Corvette and a REPLICA 56-58 hifter handle.
A 27spline drive shaft yoke (same as Turbo 350).
TOOOOOOOO EAST. Some people make it unnecessarily complicated.

[Tom P.]

Re: 58 Muncie Install Help

Oh ya, a 621 housing sorta kinda will work, but not well.
ALLLLLLLLLLL 56-62 Corvettes had an open bottom bell housing. The 56-59 was cast iron, the 60-62 was alum.
For the clutch linkage, you REALLY need an iron 56-59 housing, OR, a 60-62 alum housing------------BECAUSE the bracket for the Z-bar is attached to 2 threaded holes on the side of the bell housing. A 621 DOES NOT HAVE THESE HOLES!!!!

[Mike M.]

Re: 58 Muncie Install Help

Jason: you are getting installation info from the MOST knowledgable fella when it comes to Muncies in c-1's.they don't come more knowledgable than tom parsons. good luck with your installation. mike mccagh

[Tom P.]

Re: 58 Muncie Install Help

The first picture shows a 60-62 style alum open bottom housing, with the 2 threaded holes needed for the Z-bar bracket on a 56-62 model.
The second picture is 56-59 style open bottom iron housings with 2 threaded holes needed for the Z-bar bracket. An iron housing will work fine on any 60-62 model, BUT ALUM IS CORRECT.
The third picture compares a 60-62 housing (top housing) with a 621 style housing. As can be seen, a 621 housing has only one hole--------------AND IT IS IN THE WRONG LOCATION FOR MOUNTING A 56-62 Z-BAR BRACKET.

[Steven B.]

Re: 58 Muncie Install Help

Tom, still workin' on the B-26? Steve

[Jason P.]

Re: 58 Muncie Install Help

Thanks Tom for all the info. I am assuming then that I would go with a 1958 clutch fork to go along with the 58 bellhousing.

Thanks again.

Jason

[Tom P.]

Re: 58 Muncie Install Help

Yep, still working on the A26. Got 8 flights on it so far----------------AND STILL WORKING ON IT!!!!!!!!!!! Like an old car, there is ALWAYS something that needs to be fixed.

That's me standing, and behind the co-pilot.

https://www.youtube.com/watch?v=24lJm55rAsE

https://www.youtube.com/watch?v=4EPazwWieq4

https://www.youtube.com/watch?v=FJYBOtp4Aw4

https://www.youtube.com/watch?v=QW_1EgAmRdU

https://www.youtube.com/watch?v=rD8ukhj9x18

[Tom P.]

Re: 58 Muncie Install Help

Yep, any year will snap onto the ball stud and work in any bell housing.
I have a SB389 in my 51 Chevy with a 57 bell housing and the STOCK 51 fork with stock 51 clutch linkage. Been working fine for 50+yrs.
Just use the linkage and fork for the year model OF THE CAR.

[Roger W.]

Re: 58 Muncie Install Help

So Cool! You have really done a good job Tom.

[Roger W.]

Re: 58 Muncie Install Help

Tom. What did the factory use to lower the crossmember in 62 or was there a special crossmember?

[Mike E.]

Re: 58 Muncie Install Help

1/4” thick rectangular spacers.

[Tom P.]

Re: 58 Muncie Install Help

Yes, that is correct---------------62 ONLY, as well as the adapter plate shown above which was 62 only.
A person has to be familiar with the differences between a 55-61 and 62-later rear MANUAL transmission mount on these early cars.

The first picture shows the rear transmission mounting parts for ALLLLLLLLL 55-61 models.
The second picture shows the addition of the adapter plate, along with all the parts in the first picture, for a 62 ONLY.
The next 4 pictures show the mount pads on BW T-10 and Muncie tail housings.
The early T-10s just had the small mount pads and only used the parts in the first picture. Then in 61, many tail housings had TWO pads (depending on pass car or Corvette application).
By 62, MOST T-10 tail housings only had the big mount pad. And ALLLLLLLLL Muncies only had the big mount pad.
As can be seen, the BIG mount pad, PLUS the thickness of the 62 adapter plate, LOWERS the surface for the rear mount about 1in. Thus, the need to add 1in spacers between the rear transmission mount and the X-member of the frame.
In 55-62 Corvettes with a manual tranny, the U-joint angles are already rather extreme, so the addition of the 1in spacer is really needed.
Hope this helps.

Now, as an added comment, as well as a (personal) dig at NCRS in general, These kinds of issues and comments were strongly frowned upon and nearly forbidden by the NCRS old guard-------------------some of which still exist. I've been a member since the late-70s, but rarely participate here just because of that!

[Roger W.]

Re: 58 Muncie Install Help

CC sells the shims. Pt No. 531314. They say 2 required, so I would assume that they are one piece one inch thick.