Bubba's '66 M21 Cast Aluminum Modification Resto?

[Mike B.]

Good Morning Guys,

Here's a few shots of Bubba's handiwork on my '66 M21 original tailshaft housing's tapped boss right where the early shifter mount bracket needs to go. Back in the '70s he ground down the rear boss to accommodate the Hurst Competition Plus shifter that he'd installed. The sad part of it all is that the grinding wasn't necessary. I've since had this transmission restored and a replacement housing installed. Now I'm thinking of having the original tailshaft housing restored and having it swapped back. I'd like to treat the car to a little more originality.

Years ago I had my '65s aluminum valve covers repaired through Jerry McNeese of Camaro fame. I know that this grinding damage can be repaired. Jerry showed me photos of his aluminum repairman's artwork. The guy who did the work could even reproduce damaged Winters Snowflake logos in the cast aluminum.

I just found a contact number online for Jerry. It's a Nevada number. Looks like he may have moved from Maryland? Before I contact him I'd like to find someone through NCRS if possible who's a master at repairing this type of damage? Keep it in the family. I'd sure appreciate any information.

Thanks! Mike

Mike's '66 M21 Tailshaft before Resto (1).jpgMike's '66 M21 Tailshaft before Resto (2).jpgMike's '66 M21 Tailshaft before Resto (3).jpg

[Patrick B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Mike-- I don't think Jerry MacNeish has left Maryland. Try 410-781-0418. You will probably have to leave a message and wait several days for a reply, especially if he is on the road doing Camaro inspections.

[Robert P.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

I would think that would be apiece of cake for him he did some repair work for me and it came out perfect
Bob Peckham

[Tony R.]

[Keith B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

The guy who does Jerry’s welding welds block and heads for NHRA teams. So I am sure he does weld parts for every make

[Mike B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Thanks Pat,

It's good to hear that Jerry is still in Maryland. I certainly will contact him. Hoping he's still in the same spot. I remember the pleasant drive from my house up to his place via Maryland's eastern shore. Up and over way back in the mid-1990's.

As always, hindsight is 20/20. I know I should've gone in this direction first when I was having the previous tranny work done. Now proper casting date circles are important to me. After I have this work done I'll more accurately be able to say that the transmission has been "restored".

Take care. Mike

[Mike B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Thanks Bob, Tony and Keith,

Well it certainly sounds as if Jerry is even more active among our Corvette circle of friends than he's been in the past. Looks like he's the guy to contact unless anyone recommends someone else who's also a maestro at this type of repair work in our immediate circle?

Take care guys,
Mike

[Patrick B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Mike--- I've never looked for casting circles on a tail housing. How do you read them?

[Mike B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Hi Pat,

I found this excellent description of Muncie casting "Date Marker" and "Status Marker" circles in a very popular automotive magazine. I've seen others post info on this forum in the past about this subject but this one is real easy to grasp.

I've also included two excellent photos I recently got from my good buddy David down in Louisiana. You can see this decoding isn't as easy as this article describes. The status marker circles shown here in both example photos denote code "CM". Whatever that meant to the quality control folks it's shown in reverse typeset on one tailshaft housing and normally on the other. No matter. What we're curious about is the date marker circles. We can see that this is not an exact science either. The first example here shows a raised casting semicircular flaw which blocked the month date code outside of the circle. To confuse things even more is this a "6" or a "9" month code? The 4 dots (4th week) is very clear. The second example was a little easier to grasp. Looks like "11" (November) with 3 dots (3rd week), But there's a trace of another number present?

Hopefully your date circle is as easy to cipher as my original tailshaft housing's was. That shows an "8" (August) with 4 dots (4th week). Yes, I know we're getting into the minutiae of it all, but that's half the fun to me. Also, this could prove to be of importance to someone shopping for a very expensive Muncie transmission when it comes to authenticity.

Take care. Mike

P.S. I've found that this decoding works for other GM cast aluminum parts such as bellhousings, etc.

Muncie Casting Date Circles (2).jpgTailshaft Housing Dates David H. (1).jpgTailshaft Housing Dates David H. (6).jpg

[Joe L.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Mike------


The problem with all of these "casting circles" which are found mainly on die cast aluminum components is that there is no reference as to year. So, theoretically, that makes about half of the castings ever made "correct" for any particular car.

[Mike B.]

Re: Bubba's '66 M21 Cast Aluminum Modification Resto?

Very true Joe,

It's definitely not as accurate as most dating methods on our cars but I'm not happy with the very early month dated tailshaft housing that was installed on my tranny when it was replaced. My car is a December 1st built '66. Anyway, I'm glad I kept my original and have decided to have it repaired.

Mike