72 LT-1 distributor

[Mike G.]

is there a way i can tell if the distributor in my 72 lt1 is original? or are all tach drive distributors pretty much the same? the red foil tag says its a 1112101 distributor with a correct date which is correct for the car but it looks nicer and newer than everything else. is the foil band the only to tell what it is?

[Joe L.]

Re: 72 LT-1 distributor

is there a way i can tell if the distributor in my 72 lt1 is original? or are all tach drive distributors pretty much the same? the red foil tag says its a 1112101 distributor with a correct date which is correct for the car but it looks nicer and newer than everything else. is the foil band the only to tell what it is?

Mike----


The aluminum band, assuming it's original to the distributor, is the only way to tell, for sure, what the distributor is. It's also possible to "narrow down" the original distributor part number by identifying the installed main shaft with auto cam, weights, springs, and vacuum control. Of course, these parts could also have been replaced along the way. Also, it's very difficult to identify the installed mainshaft, weights and springs.

By the way, if any of the above parts have been replaced with non-original spec parts, the distributor is no longer the part number shown on the band, even if the band is original to the distributor.

[Mike G.]

Re: 72 LT-1 distributor

that answerd my question. thanks for the help.

[Tom L.]

Re: 72 LT-1 distributor

I rebuilt my distributer this past fall and the band said it came out of a '74 (don't remember if it was small or big block). I replace the internals and VAC with the cotrrect parts but did not replace the weights or mainshaft.

Your comments made me wonder, do they differ from year to year and app. to app? If so how would you tell? Visually or on a SUN machine? Thanks!

[Wayne M.]

Re: 72 LT-1 distributor

is there a way i can tell if the distributor in my 72 lt1 is original? or are all tach drive distributors pretty much the same? the red foil tag says its a 1112101 distributor with a correct date which is correct for the car but it looks nicer and newer than everything else. is the foil band the only to tell what it is?

Mike -- you've had good advice so far, but a quick way is to check the obvious externally visual items, like the hole in the cast iron opposite the tach drive gear, (for the nylon thrust button); this feature was added sometime in the summer of 1970. Also the vac. advance [I don't have a '72 judging manual, but] the Delco spec books call for 1973437, so you can check for 437__15 stamped on the flat bracket almost under the distributor cap. There's been a lot of posts and pics recently on this particular vac can.

Maybe another is to lift the cap and check for the presence of points shielding mount holes in the points and condenser plate (that rotates a bit when the vac advances).

Of course, as mentioned, much of this can be changed, but at least it's easy to check.

[Joe L.]

Re: 72 LT-1 distributor

I rebuilt my distributer this past fall and the band said it came out of a '74 (don't remember if it was small or big block). I replace the internals and VAC with the cotrrect parts but did not replace the weights or mainshaft.

Your comments made me wonder, do they differ from year to year and app. to app? If so how would you tell? Visually or on a SUN machine? Thanks!

Lynn-----

The weights and mainshaft definitely varied by year and application. There really were not a lot of different weights. However, there were a LOT of different mainshafts (actually, the shafts are pretty much all the same, but the "autocam" brazed to the top vary).

Some of the autocams are stamped with an alpha/numeric or numeric code, but I don't have a key that relates code to shaft part number. The weights are not marked, but may be identified by configuration. The springs are obviously not marked and it's very hard to identify them as to part number by configuration.

A distributor could be checked with a distributor machine to see if it met original specs. However, that does not mean that all internal parts are original. Of course, if it meets original specs, it does not really matter if the internal parts are original, or not. No one will ever know the difference.

[Tom L.]

Re: 72 LT-1 distributor

Thanks, when I did the job all that was in my head was "the distributors are interchangable". I knew the VAC was different from appp. to app. but didn't consider the weight set-up. I'll have to bring it somewhere and give it a spin next time it's out of the car.

All is running OK for now so it will hopefully be a while! Thanks!

[Jim T.]

Re: 72 LT-1 distributor

Mike -- you've had good advice so far, but a quick way is to check the obvious externally visual items, like the hole in the cast iron opposite the tach drive gear, (for the nylon thrust button); this feature was added sometime in the summer of 1970. Also the vac. advance [I don't have a '72 judging manual, but] the Delco spec books call for 1973437, so you can check for 437__15 stamped on the flat bracket almost under the distributor cap. There's been a lot of posts and pics recently on this particular vac can.

Maybe another is to lift the cap and check for the presence of points shielding mount holes in the points and condenser plate (that rotates a bit when the vac advances).

Of course, as mentioned, much of this can be changed, but at least it's easy to check.

I have read before that late 1970 Corvette models had the hole drilled in the distributor casting for the nylon button. My original owner, original distributor in my 1970 Corvette built in July 1970 does not have this late model feature. Engine from the factory 350/300. I wish it would of had this improvement.

[Wayne M.]

Re: 72 LT-1 distributor

I have read before that late 1970 Corvette models had the hole drilled in the distributor casting for the nylon button. My original owner, original distributor in my 1970 Corvette built in July 1970 does not have this late model feature. Engine from the factory 350/300. I wish it would of had this improvement.

Jim -- I think your late 1970 case, coupled with the early '71 LT1 distr I have [1112038__0_J_3], Sept 3rd, 1970, WITH hole, pretty well narrows it down.

[Terry M.]

Re: 72 LT-1 distributor

I wouldn't want to base the change over on just two examples. I would have to look at the TIM&JG to be sure, but I think we called the change around 12K s/n. It would have been more accurate to track engine assembly dates, but we didn't. We should also have allowed for the potential difference between the two engine plants.

[Mike G.]

Re: 72 LT-1 distributor

a seller on ebay has a 1116163 \ 163-16 vac advance he claims is for a 70 to 72 lt1 corvette. my book shows a 201-16 for 70 and a 437-16 for 71 and 72. what does that 163 fit?

[Wayne M.]

Re: 72 LT-1 distributor

a seller on ebay has a 1116163 \ 163-16 vac advance he claims is for a 70 to 72 lt1 corvette. my book shows a 201-16 for 70 and a 437-16 for 71 and 72. what does that 163 fit?

Mike --- the 1116163 is an old part # (circa 1963) that, AFAIK, was never used on any production distributor, up to and including the C3's. (source Delco Test Spec supplements).

It does show as a service vac advance in my '70 P&A30B catalog, serving various distr. from '59 thru '69-70 w/T/I, none of which came originally equipped with it. Spec's are: 8-10" Hg to start advance; 16.25 to 18" Hg for max adv.; max distr. advance 8 degrees (ie. 16 crank degrees).

[Joe L.]

Re: 72 LT-1 distributor

Mike --- the 1116163 is an old part # (circa 1963) that, AFAIK, was never used on any production distributor, up to and including the C3's. (source Delco Test Spec supplements).

It does show as a service vac advance in my '70 P&A30B catalog, serving various distr. from '59 thru '69-70 w/T/I, none of which came originally equipped with it. Spec's are: 8-10" Hg to start advance; 16.25 to 18" Hg for max adv.; max distr. advance 8 degrees (ie. 16 crank degrees).

Wayne-----


Yes, the GM #1116163 vacuum control was not used in PRODUCTION. At least, it was not used in PRODUCTION for any Chevrolet distributor application. However, it also had Buick applications. It may be that it was used in PRODUCTION for Buick applications and, since it was so close, or possibly even identical, in spec to a control used for Chevrolet applications, it was decided by GMSPO to "consolidate" it for the purpose of Chevrolet SERVICE applications.

Notwithstanding the above, although I have absolutely no empirical information to support this, I would not rule out the possibility that it was used alternately in PRODUCTION for Chevrolet applications.

[Mike G.]

Re: 72 LT-1 distributor

i asked the seller where he got the information... said he made a mistake and took it down. i am looking for a nos replacement for my 70. if i cant find one i will use the original. it still works but it looks bad.DSC00701.JPG

[Mike G.]

Re: 72 LT-1 distributor

what is the difference between a 437-15 and a 437-16 vacuum advance. the book shows the 437-16 to be correct but all of the rebuilt distributors i see have the 437-15. would i get docked points for that?