Need Urgent Help on 65 TI distributor

[Keith B.]

I need help indentifying a TI distributor for a 1965 396 engine. I have seen several differences in the oil galleys at the bottom of the shaft. If anyone has a casting number (not the part number of the distributor) of the shaft I would be in great appreciation. A picture would be most helpful. If you describe please give very detailed description.

Can there be any damage to the motor if the shaft isn't the one for the car.

Thanks as always.

Keith

[Terry F.]

Re: Need Urgent Help on 65 TI distributor

I believe you are talking about the rear camshaft bearing area and how the destributor housing sits in that area. That area is critical to getting the proper amount of oil to the top end of the engine. Can't say if you damaged anything but I know it must be set up right. Most important is the rear cam journal and the rear cam bearing. I believe the distributor housing may or may not have a groove in it to assist in the passage of oil in the region. But, basically I shouldn't be commenting because I know just enough about this to get into trouble on the subject. Someone will respond that knows much more than me. Terry

[Joe L.]

Re: Need Urgent Help on 65 TI distributor

Keith-----

There are only 2 different configurations of the distributor housings relative to the issue of concern to you. These involve the "full round" oiling groove versus the "280 degree" oiling groove. I believe that 1965 L-78 distributors used the "280" degree" oiling groove configuration.

The "280 degree" configuration is depicted on the left, below. The "360 dgree" configuration is depicted on the right.

[Wayne M.]

May be more complicated than just the distrib.

Read the left hand column [from How to HotRod BB Chevs]. The distributor 280 degree annulus that Joe L. shows goes hand-in-hand with the configuration of the camshaft rear journal and bearing.

I'm no expert (maybe Duke W. knows) but I would be sure to get the latest opinion on use of the above components before installing a partially grooved distr. in either BB or SB.

[Bill W.]

Re: Need Urgent Help on 65 TI distributor

Keith , I have the orig. dist. out of # 16120 it is a 093..dated 5g8 and has a 110 cast into the shaft housing. the grove goes all the way around like Joes rt side photo .....Bill

[Joe L.]

Correction and Additional Information

Keith------

Forget what I said earlier regarding the applicability of the "280 degree" oil channel for your 1965 L-78 distributor. Here's the story: the VAST majority of 62-74 Corvette distributors (and, also, those distributors used for most other 62-74 Chevrolet applications) used the "360 degree" oil channel. Myself (and, many others) have for years considered that the "280 degree" versions were used for the 65-66 big block applications due to the oiling differences found on these engines. However, I've done some more research and, based on what I've found so far, I think that I can say that MOST original 62-74 Corvette distributors used the "360 degree" oil channel housing. I'm not 100% certain of that yet, but from what I've found I feel very confident that was the case. I am now 100% sure that ALL 1962-74 Corvette distributors CAN USE the "360 degree" oil channel configuration WHETHER OR NOT THEY WERE ORIGINALLY EQUIPPED WITH A DISTRIBUTOR WITH SUCH CONFIGURATION.

So, what distributors used the "280 degree" oil channel configuration? Well, keep in mind that Chevrolet distributors are, basically, interchangeable between small blocks and big blocks. Furthermore, they're interchangeable between BOTH big blocks-----Mark I and Mark IV. Mark IV big blocks are those that were installed in Corvettes from 1965 through 1974. Mark I big blocks were never originally installed in Corvettes----they're known as the 348 and 409. I now believe that the "280 degree" oil channel configuration is a feature of the distributors used in these engines.

The above does not explain the existence of some Corvette tach-drive type distributors with the "280 degree" oil channel configuration. No Corvettes were ever fitted with 348 or 409 cid engines and, with minor exceptions, Corvettes were the only Chevrolet car that used tach drive distributors (a few Z-28 Camaros were also fitted with this type distributor on an RPO basis). I do think that some Corvette big blocks did use the "280" degree configuration but I now think that it was likely that it was 1967 and later engines. To wit, the distributor that I have pictured on the left side with the "280 degree" oiling configuration is a GM #1111263. This was a SERVICE-only distributor used for big blocks with gear drive cams. No PRODUCTION big blocks were ever made with this feature, so this distributor was never used in PRODUCTION engines. Also, this distributor uses a special housing designed for a ball bearing supported shaft and without provisions for vacuum advance. However, as you note, it does have the "280 degree" oiling. Since this distributor was designed for use in 67+ big block engines and since the oiling systems in all 67+ Mark IV big blocks were the same (EXCEPT ZL-1), it follows that the "280 degree" oiling design can be used in 67+ big block engines. "Extrapolating" from this (which often gets me into trouble), it MAY also be the case that some 1967+ Corvette big block distributors for PRODUCTION engines also used the "280 degree" configuration. I have no idea why, though. I am 100% certain that the "360" degree oiling configuration will work for 1967+ big blocks and I have many NOS distributors for 1967+ big block engines that have the "360 degree" configuration. I do not know, though, that ALL 67+ big block distributors were so-designed and manufactured.

[Mike McKown]

Another tidbit

I have a '69 375/396 that came new in a Camaro. Not a tach drive distributor but aluminum and it does have what you refer to as a 280 degree distributor housing.

[John H.]

Re: Another tidbit

The August, 1973 P&A30B calls out the same distributor housing (#1851158) for ALL 1962-1974 Corvettes. As far as I know, there is no connection between the '65-'66 big-block rear cam bearing issue and the configuration of the oil annulus on the distributor housing (at least for any production-released parts).

[Joe L.]

Re: Another tidbit

John-----

Yes, the GM #1851158 is the "360 degree" oiling configuration. There were, however, several earlier distributor housing part numbers that were all "merged into" the 1851158 prior to 1973.

Earlier, there were actually separate part numbers for distributor housings used for small blocks and big blocks, including at least 2 different part numbers for both small blocks and big blocks for a total of at least 4 different housing part numbers. The only possible difference that I could imagine would be for this oil annulus configuration. In any event, all of these were superceded by the 1851158, so whether some of the earlier ones were "280 degree" configuration, or not, the "360 degree" configuration must work for them.

The 348/409 housing was NOT superceded by any other part number, though. It was discontinued without supercession in 1973.

[David D.]

Re: Another tidbit

Joe, I may be wrong, but I seem to recall the 348/409 distributor housing being shorter than the Gen I small block distributor housing. If remember correctly, it was shorter between the underside of the flange that butts down on the intake manifold, to the end of the housing, just before the shims for the cam driven gear. I hope I explained it correctly. If not, I'm sure someone will correct me. Dave

[Mike McKown]

Re: Another tidbit

I think you're right.

[Joe L.]

Re: Another tidbit

Dave-----

You are absolutely correct. For years, I've been told by many folks (some of whom I really thought knew what they were talking about) that the 348/409 distributors were interchangeable with the small block and Mark IV big block distributors. I have no personal knowledge of the 348/409 engine series since I've never been into any or had much to do with any. So, I've pretty much been relying on what I've been told. Well, what I've been told is totally inaccurate. As it turns out, I've confirmed that the 348/409 distributor housing is about 3/8" shorter than the housings used for small block and Mark IV big block. So, there's no way that a 348/409 distributor is interchangeable with the other engines or vice-versa. The 348/409 distributor does use the "280 degree" oiling configuration, though.

Another "urban myth" debunked and another useful piece of information garnered for my "memory banks".

[David D.]

Re: Another tidbit

Joe, Thanks for confirming what I remember, from "my memory banks". I was not sure about the oiling configuration of the groove, that's why I didn't mention it. Dave