[unruhjonny]

I'm not exactly sure where to post this, so hopefully this is a fine spot;

I was wondering if anyone might be able to help me out with interchange, or if a suitable part is being currently manufactured to use.

I have a 1963 Muncie main case #3831704;
Long story short, my brother bought it, and I am wondering about the viability of using it - the thing is in perfect condition.
I have a 1968(?) M20 that has a repaired main case, and it could probably need a rebuild anyway, so I am wondering if I was to rebuild it, if it might make sense to rebuild it using this case.
(I could bore it for the larger countershaft, but the smaller front bearing would presumably have to stay.)

I understand from my 'rebuilding Muncie' book that the original smaller diameter front bearing worked with a specific very hard to find (aluminum) front bearing retainer, and that a saginaw front bearing retainer #592620 is a viable (cast iron) replacement;
I did some searches and it appears that this 'saginaw' bearing retainer is for a 1955-1957 Corvette, and there are at least three on ebay right now.

Question #1: Does anyone know the full application for the this "saginaw" bearing retainer?
(or was this specific to 55-57 Corvettes?)

Question #2: Does anyone know if a replacement (cast iron) front bearing retainer that would work for me is currently being manufactured?
(I bought a AGE front bearing retainer for another Muncie, and in addition to it being a great brand new part, it came in at less than OE pricing)

Question #3: Is it anyone's opinion that I throw away the idea of ever using this main case?
(Does anyone know if, or believe that this smaller front bearing will become an issue if I was to run it behind a Pontiac 400?)

Thanks to anyone who might speak up!

[unruhjonny]

Just adding some pictures incase it prompts a reply

The case in question:



Here is the quote from the Muncie book:


And here is one of the ebay listings which gives an application of sorts:

[AC445]

Hello,call Dennis at DME transmission .He sets up at the Tri-Power Nationals and also rebuilds shifters.I'm sure he can help , 606-237-6648 ,I don't have his e-mail. Good Luck

['ol Pinion head]

Not up on the "704" case Muncies small bearing retainers. Will note the "704" & the "325" case Muncies use the 7/8" diam cluster pins. These early case Muncies are NOTORIOUS for the stretching of the pin hole in the alum case. Nearly 20 years ago in a combined effort to build up several early Muncies using up what had been stretched pin hole "325" cases, an old friend I had a local retired machinist setup & remachine (with a slight taper) the cluster pin holes in each of three "325" cases to accept later 1" diam cluster pins. Doing so required building each transmission using later M20 inputs, '66-74 cluster gears, main shaft gears, as well as later style style sliders. If we had not owned a bunch of loose Muncie parts, we wouldnt have even messed with these 325 case M20 Muncies. Each had been basically bought cheap as boogered up Muncies over the year in multiple transmission package deals. End result was two early GTO's as well as '65 442 each received a fresh rebuilt 2.52 1st gear M20 in a "325" case. Each may not have been their born with original M20, but all reasonably dated the cars they went in, & each was a better stronger M20 than what originally came in each car.

[unruhjonny]

I am going to bump this thread (I looked for info before creating an entirely new thread, and figured I'd just use this one).

I was recently thinking of buying this off my brother, and setting it up as a step in replacement for the M20 Main case I have on my work bench - which has two or three ugly welded up ears (it also have some side cover bolt holes stripped).

When I spoke to a local about this, he reminded me about small front bearing, and smaller front bearing retainer.

Now I want to slightly pivot from my original question;

Here's my new question:

If I bought a cast iron saginaw front bearing retainer, and had the case drilled for a 1" mainshaft, would the smaller front bearing become a liability?

This is such a beautiful case, I would think that I could put it into service - specifically in place of a non-numbers M20 with an ugly main case.

[chrisp]

In my opinion the answer is No, S&K has the retainer for small bearing large o.d. flange they have had them made for years now , a properly built 7/8 pin small bearing muncie is very reliable for street use .

[unruhjonny]

Who is "S&K"

I was looking for used/NOS saginaw bearing retainers mentioned in the Muncie book (pictured in post #2)

[unruhjonny]

Does anyone know who "S&K" is?

[Held for Ransom]

SKF bearings.
https://www.thegearbox.org/catalog/i...82/9514567.htm