C-3 Distributor ID

[Christopher K.]

I am rebuilding the distributor on my '73 L82 4spd. After reading the tech info manual and some posts in the archives, I'm wondering if my distributor is original.
I have no ID tag. There is no "hole" for the set screw opposite the the tach drive cable. The manual says earlier distributors did not have this. Do they mean earlier '73, or earlier as in C2 distributors? My car is a Mar '73 build.

Thanks in advance for any help,
Chris

[Joe L.]

Re: C-3 Distributor ID

I am rebuilding the distributor on my '73 L82 4spd. After reading the tech info manual and some posts in the archives, I'm wondering if my distributor is original.
I have no ID tag. There is no "hole" for the set screw opposite the the tach drive cable. The manual says earlier distributors did not have this. Do they mean earlier '73, or earlier as in C2 distributors? My car is a Mar '73 build.

Thanks in advance for any help,
Chris

Chris-----


Generally, it's thought that the tach drive gear thrust button, the reason for the hole in the end of the tach gear cavity, began about mid-1970. So, it's extremely likely that your original distributor would have had the hole. Distributors before about mid-1970 did not have the hole; that's the "earlier" the manual is referring to.

By the way, there were no threads in the hole and no set screw was originally installed. That configuration is retrofit only.

[Jim T.]

Re: C-3 Distributor ID

My late build July 1970 Corvette's distributor does not have a hole for the thrust button. This is the same distributor that was in it when I bought it new.

[Joe L.]

Re: C-3 Distributor ID

My late build July 1970 Corvette's distributor does not have a hole for the thrust button. This is the same distributor that was in it when I bought it new.

Jim-----


That's good information. I've never been really sure when the addition of the thrust button actually occurred. I've done a little research on the matter and it now appears to me that the change might not have occurred until sometime in the 1973 model year.

It would be interesting to hear from folks with 1970-73 Corvettes with distributors that they're reasonably sure are original to the car and unmodified with respect to the thrust button.

[Terry M.]

Re: C-3 Distributor ID

Joe,
My early 11970 (engine V0114CTU) has NO hole.

I'm real confident of the mid-1970 change to the distributor with the button. Maybe Jim's late in the model year engine got the last of the 1970 distributors that were lying around. We did our research on that feature, and the other ignition changes over twenty years ago when folks cared a lot less about these kinds of details and there were more unmolested C3s around than there are today.

[Christopher K.]

Re: C-3 Distributor ID

Thanks very much for the responses, it's greatly appreciated.

My car is very original and sat for about 15 yrs. Block, trans, carburetor, intake, fuel pump, master cylinder, and smog are all original. I find it very mysterious why someone would swap out the distributor.

Maybe Lyle will post and share his experience with his '73's.

Chris

[William C.]

Re: C-3 Distributor ID

Just out of curiousity, what numbers are on the vacuum advance? The '73 original should be unique to that distributor.

[Jim T.]

Re: C-3 Distributor ID

Terry and Joe, Dave Strickland has a 1970 LT-1 with a VIN number a few numbers after my 1970, perhaps he will post what his LT-1 came with. My 70 was the base engine, perhaps the 70's engine HP had something to do with the model year change.

[Martin N.]

Re: C-3 Distributor ID

My 1974 L-48 / THM 400 with distributor tag #1112247 / 4 A 29 (Jan. 29 1974) build date DOES have the "hole" for the tach gear thrust button.

I do believe this distributor is original to the engine / car combination.

Marty

[Christopher K.]

Re: C-3 Distributor ID

Bill,

I took off the inop vacuum can about a year ago. I remember it was not the correct can (I did save it) but assumed at the time that the previous owner had put on an incorrect part. I bought the correct replacement from napa, I believe a B26.

I'll take a look at those numbers when I get home tonight.

I also remember a discussion referencing the higher hp engine distributors. It would be interesting to see if some of these did not have the hole.

Thanks for all the help guys,
Chris

[Christopher K.]

Re: C-3 Distributor ID

I looked at my old vacuum control this morning. It says MS and under that, 201 15. I do recall the previous owner saying he swapped this out. Obviously the wrong application.

There's also a Patent number on the breaker plate, 2769047. I don't know if that offers any clue to the date of production.

Thanks,
Chris

[Timothy B.]

Re: C-3 Distributor ID

Christopher,

A 201 vacuum can is used on 63 corvette distributor and I believe (not positive) some big block applications. Try to look under the weight base and identify the #'s stamped into it, this part is the plate the advance weights ride on. This may give a indication of it's use. The #'s should read something like 724 CCW if it's a 63 distributor.

[Christopher K.]

Re: C-3 Distributor ID

Tim,
After some cleaning and a little mirror manipulation I was able to look at those numbers. They are CCW 524 - I'm very sure it's not a 7.

I also did a little surfing on Fleabay and saw a listing for an nos '70 TI distributor. It also had the MS 201 15 vacuum can.

Thanks for the good info, I would have never looked there.

Chris

[William C.]

Re: C-3 Distributor ID

OK let's go back to what we know here. You have a '73 L-82 4 speed. You need a distributor part number 1112130. That distributor should have a housing with a hole in the housing at the area where the cross-shaft for the tach drive bottoms out, and a small thrust button (nylon) located in the back of the housing with a small pin that sits in the hole in the housing to center the thrust button. The vacuum advance should be marked 448. The housing with the hole in them all interchange, but looking at a TI model just gives you a housing (maybe without the hole) and a set of shafts. Far better to look for a correct distributor or at least a standard points-type unit from a '71-74 that can be rebuilt into the one you need, assuming you can't actually find a real 1112130 with a correct tag. about any '71-74 tach drive distributor should give the basic parts to build what you need. Be careful if you buy a reproduction vacuum advance as they do not always faithfully reproduce the original advance curve of the GM parts.

[Christopher K.]

Re: C-3 Distributor ID

Thanks for the advice Bill,
Chris