Need help identifying center section

[Michael A.]

Hi all,

I recently picked up a rolling 57 corvette chassis to use for parts. The center section has me puzzled. It is a 3725899 casting no. which should be good for a 57,, but it has not been stamped with a build sequence and also has no build date on the drivers side. The only markings beside the casting number are a large GM and an M in a square. There is also a rectangular marking in between the GM and the M in a square. I have never had a pumpkin without dates and assy. data. Can anyone shed any light on this? Thanks in advance and Happy New Year to all.
Later Mike

[Gary C.]

Re: Need help identifying center section

Mike, can you post some photos? Have never see a rear end pumpkin without a cast date. What about the axle housing itself. Are the brake backing plate flanges on the housing perpendicular to the ground or at an angle - approximately 25 degrees? Does the axle housing have a drain plug or not? Happy New Year, Gary....

[Michael A.]

Re: Need help identifying center section

Hi Gary,

Here are some photos of the pumpkin. Let me know what you think. It has me confused.

[Gary C.]

Re: Need help identifying center section

Michael, beats me as have always seen cast dates on them. Parts counter replacement units didn't have any assembly code/date stamped on them. Even on the 65 passenger car units. Maybe some of the other TDB Members will have some ideas as to it's origination. Thanks for posting photos. BTW, are the brake backing plate flanges rotate or perpendicular to the ground? Gary....

[Michael A.]

Re: Need help identifying center section

Hey Gary,


The backing plates are rotated. If need be I can post pictures of them.
Later Mike

[Joe L.]

Re: Need help identifying center section

Hi Gary,

Here are some photos of the pumpkin. Let me know what you think. It has me confused.

Michael-----



The "M" in the square looks like it might represent a manufacturer's id mark. If that's what it is, it might indicate that this casting was manufactured by a foundry other than the GM's Saginaw or Tonawanda foundry where all of these are thought to have been cast. It MIGHT represent McKinnon Industries, which was a Canadian predecessor to GM's St. Catherine's Ontario foundry, now also closed.

[Gary C.]

Re: Need help identifying center section

Mike, if they're rotated it's a Corvette axle housing. Check when you take the pumpkin out to see if there are baffles right inside the axle tubes and a "V" like oil dripper over the ring gear. Thanks, Gary....

[John H.]

Re: Need help identifying center section

The "M" in the square looks like it might represent a manufacturer's id mark. If that's what it is, it might indicate that this casting was manufactured by a foundry other than the GM's Saginaw or Tonawanda foundry where all of these are thought to have been cast. It MIGHT represent McKinnon Industries, which was a Canadian predecessor to GM's St. Catherine's Ontario foundry, now also closed.

Joe -

I believe that's correct - my history of McKinnon Industries shows that they were in the Chevrolet axle business at that time.

[Michael A.]

Re: Need help identifying center section

Guy's, that makes sense because this chassis came out of Canada. It has been in the same family since 1968 in Canada. Maybe the pumpkin could have been changed earlier because this was a drag car prior to this family purchasing it.
Thanks Mike