Need Bellhousing for a Late '56

[Edward M.]

Re: Need Bellhousing for a Late '56

For '57, both passenger car and Corvette used the same casting number bellhousing (3733365), but that casting was machined differently for each application.

For passenger cars, the 365 casting was machined for the inside-installed 7/16"-20 ball stud (#3836314), and the finish-machined bellhousing carried P/N 3733365 (same as the casting number). This application used clutch fork P/N 3737454.

For Corvettes, the 365 casting was machined for the outside-installed 13/16"-16 ball stud (#3729000), and the finish-machined bellhousing carried P/N 3733369. This application used clutch fork P/N 3739043.

OK, so, if I read this correctly, a passenger car bellhousing would have a 7/16"-20 hole drilled and tapped. A Corvette bellhousing would have a 13/16"-16 hole drilled and tapped.

In both cases, the ball stud is removable.

It seems to me that a decent machinist could take a passenger car bellhousing, drill and tap the 7/16"-20 hole out to 13/16"-16, then install the correct ball stud.

Any reason why that would not work?

[Joe L.]

Re: Need Bellhousing for a Late '56

OK, so, if I read this correctly, a passenger car bellhousing would have a 7/16"-20 hole drilled and tapped. A Corvette bellhousing would have a 13/16"-16 hole drilled and tapped.

In both cases, the ball stud is removable.

It seems to me that a decent machinist could take a passenger car bellhousing, drill and tap the 7/16"-20 hole out to 13/16"-16, then install the correct ball stud.

Any reason why that would not work?

Ed------


Yes, I THINK that would work. The boss on the casting is designed so that either type of ball stud tapping could be performed at the machining plant where these things were originally machined.

However, what I don't know is if either tapping was done on exactly the same center. If not, if a Corvette tapping was subsequently performed on the same center as the original passenger car tapping "it might not come out right".

[Edward M.]

Re: Need Bellhousing for a Late '56

Ed------


Yes, I THINK that would work. The boss on the casting is designed so that either type of ball stud tapping could be performed at the machining plant where these things were originally machined.

However, what I don't know is if either tapping was done on exactly the same center. If not, if a Corvette tapping was subsequently performed on the same center as the original passenger car tapping "it might not come out right".

I have seen both the small and the large bellhousing holes and they both seem to be in the center of the boss.

[John H.]

Re: Need Bellhousing for a Late '56

It would appear from looking at the boss in the casting that there was only one location for the stud, either inside or outside-installed.

[Brooks G.]

Re: Need Bellhousing for a Late '56

Ed,
It would not be a problem drilling and tapping the hole for 13/16-16 for me as I have done machine work for over 30 years before I retired. I am lucky that I still have access to a lathe and milling machine. The cost of the tap might be a bit prohibitive. I would have to research that. There would probably also be additional machining for the piece I see on many cast iron bellhousings that requires an allen wrench to remove (counterbore?). I guess one would have to weigh the cost of machining a bellhousing that is not correct verses buying one that is already correct. As for me the search continues. Thanks for the input! Brooks Glover (2141)

[Edward M.]

Re: Need Bellhousing for a Late '56

Ed,
It would not be a problem drilling and tapping the hole for 13/16-16 for me as I have done machine work for over 30 years before I retired. I am lucky that I still have access to a lathe and milling machine. The cost of the tap might be a bit prohibitive. I would have to research that. There would probably also be additional machining for the piece I see on many cast iron bellhousings that requires an allen wrench to remove (counterbore?). I guess one would have to weigh the cost of machining a bellhousing that is not correct verses buying one that is already correct. As for me the search continues. Thanks for the input! Brooks Glover (2141)

Brooks;

My point is that finding a correct Corvette style bellhousing may be difficult. You need a single or dual four barrel, manual trans passenger car or Corvette bellhousing.

I suspect that there were a lot more two barrel, manual trans passenger cars made than one or two four barrel cars.

Ideally, you would find the correct bellhousing. But if not, you have another option.

A single tap can't cost that much. I see ads on Ebay for used, professionally resharpened ones (two of them) for $5.99. A new one is about $30 on Ebay.

We are still trying to figure out if late 56 cars came with a 365 bellhousing. Mu suggestion is to locate one with the correct date code, and don't worry about whether it is a 922 or a 365.

The change from 922 to 365 occurred somewhere between February 25 of 56 (early 56 model year) and October 24 of 56 (early 57 model year). We are trying to narrow that window down some.

Does anyone have either a 922 or a 365 that is dated between these two dates? If so, which casting number is it, and what is the date code?

The research continues. Stay tuned.....

[David B.]

Re: Need Bellhousing for a Late '56

I have a 365, dated L116 for my December '56 built '57. Here are some pictures. Hope this helps.

Dave

[Joe L.]

Re: Need Bellhousing for a Late '56

Ed,
It would not be a problem drilling and tapping the hole for 13/16-16 for me as I have done machine work for over 30 years before I retired. I am lucky that I still have access to a lathe and milling machine. The cost of the tap might be a bit prohibitive. I would have to research that. There would probably also be additional machining for the piece I see on many cast iron bellhousings that requires an allen wrench to remove (counterbore?). I guess one would have to weigh the cost of machining a bellhousing that is not correct verses buying one that is already correct. As for me the search continues. Thanks for the input! Brooks Glover (2141)

Brooks------


There is a counterbore for the 13/16-16 thread size ball studs. So, it will require multiple machining operations to re-work a bellhousing to accept the 3729000 ball stud.

[Tom P.]

Re: Need Bellhousing for a Late '56

Tom------


I didn't mean to imply that any '365' bellhousings used the smaller thread size ball stud fitting (i.e. the one that installs from inside the bellhousing). However, I can't say, for sure, that none did. So, to cover that base, I advised checking to be sure of the ball stud tapping size.

And I didn't mean to imply that you implied that I implied (did I say that right? ) that 365 housings did or did not get delivered with both small and large ball studs. I have just never seen a 365 housing with the small stud.

[Jeff H.]

Re: Need Bellhousing for a Late '56

Interesting discussion of the 56 bellhousing. If anyone is interested i have a bellhousing #3733365 dated A217. Sorry i did not get to you sooner but i was busy preparing for a car show this weekend. Jeff