vacuum advance for 1111258 TI

[Howard Nardick]

Can someone please tell me the correct vacuum advance for a 1967 427/435hp TI distributor?? #1111258

THANKS IN ADVANCE!! HN

[Duke W.]

Re: vacuum advance for 1111258 TI

Your engine was originally equipped with a ported vacuum advance and the vacuum advance specs are 0@8", 15@15.5". I don't have the original part number, but if your advance is original the last three digits and maximum advance are stamped on the vacuum can bracket. It might be 201 15.

What does yours say?

I recommend you convert to full time vacuum advance and use a NAPA/Echlin VC1765, which is stamped "B20". This can is 0@6", 16@12", and you engine will produce enough idle vacuum at 900 with full vacuum advance to keep the plunger pulled to the limit at idle, which is what you want.

Full time vacuum advance will improve fuel economy and reduce any tendency to run hot at idle and low speed driving.

A convenient source of full time manifold vacuum is the carb choke vacuum break and there may be other sources such as a fitting on the manifold.

Duke

[Michael H.]

Re: vacuum advance for 1111258 TI

Howard,

Interesting question. According to several GM parts books, there is no such thing as a vacuum advance unit for a 67 435 HP. Obviously, this is not the case, but for years, the error has been in the books. There are vac adv units listed for every other possible combination of 67 big block but not the 67 with 3x2/435 HP.

A 1969 printing does list an 1115355 for 66-67 (427) (exc Sp H/Per) and on the same page, lists 1115360 for 67-68 427 w/4BC, but again, nothing for the 435. A 1973 printing shows the same.

Recently, there have been rumors of the correct original being an 1116201 but I highly doubt that probability as that was a unit used on distributors for the 1963 model and discontinued/replaced some time in 1964 by the 1116163.

My guess? It's the same as a 1966 425 HP, which is supposedly a 1115360. Hope to hear from others with original 67 435 cars or original 258 distributors.

Wonder what a 1967 printing of the parts book shows for this app? Bet Joe Lucia has one.

Michael

[William C.]

Re: vacuum advance for 1111258 TI

Mitchels shows P/N 1116201 as the vac advance unit for the 1111258 dist. Delco Remy Test specs agrees. 7-9 inches to start adv, all in at 15 inches, 8 degrees distributor advance.

[Michael H.]

Find The Hidden 435 In This Picture And...

...win a prize. And also find the mysterious 1116201 vacuum advance unit and win the grand prize.

This is a 1969 printing of the GM parts book. If you look through all of the listings, you will see that there is no such thing as a vacuum advance unit for a 67 427 W/Sp. H/Per. (435) (maybe there's no such thing as a 435?)

Actually, there are two listings for 67 with 427 so I have to assume one is the correct unit for 435 and it's likely the same as the 65-66 427 W/ Sp. H/Per. (425 HP)

Also missing is any mention of an 1116201 vacuum advance unit. Not at all surprising as it was the unit specified for 63 and 64 but was discontinued as of January 1965, and replaced by the 1115163, another nearly identical unit for small block, not big block.

[Duke W.]

Re: vacuum advance for 1111258 TI

I have both '63 and '67 AMA specs and the vacuum advance specs are identical for both '63 and '67 L-71 down to the half-inch Hg, (0@8", 15@15.5") so it's conceivable that both have the same vacuum can.

The '63 final three digits are 201. Is everyone certain that the first four are 1116 and not 1115? 1116201 doesn't seem to jibe with production use, which I believe is earlier than '63.

It's also conceivable that the 201 can could have been replaced for service, but brought back for a production engine. Maybe it's a case of the right hand not knowing what the left hand is doing, but it's possible.

That's why I asked for the numbers on his vacuum can.

I believe the 1115360 specs are 0@6" 12@12".

The lack of a correct listing in the parts catalog for '67 L-71 is just another error of which there are many, many, many...

Duke

[Joe L.]

Re: vacuum advance for 1111258 TI

Michael, et al-----

Yes, I have several editions of the 1967 P&A Catalog. However, they won't be of any help as the vacuum control for the 1967 L-71 application is not catalogued. It's an omission. What's more, it's an omission that "repeated itself". Having never gotten into the 1967 P&A Catalog resulted in its NEVER inclusion into any subsequent Chevrolet or Corvette P&A Catalog.

However, we have other sources of information. The original vacuum control for the 1967 L-71 distributor (GM #1111258) was GM #1116201. This vacuum control was discontinued from SERVICE in January, 1965 and replaced by the GM #1116163. However, as was fairly common for these vacuum controls, the '201' continued to be used in PRODUCTION after that time. I don't know, for sure, if any 1116163 controls were ever installed in PRODUCTION on the 1111258 distributor, but they may have been. The 1116201 was used in PRODUCTION until, at least, 1971 for several distributors. Why discontinue it from SERVICE but keep using it in PRODUCTION? I don't know. It's one of the "great mysteries" of the GM parts system. Like I say, though, this "phenomenon" was fairly common for these vacuum controls.

So, while the GM #1116201 was used in PRODUCTION for most or all GM #1111258 distributors, the only vacuum control that you could ever get in SERVICE for that distributor was the 1116163 (since the 1116201 was discontinued from SERVICE before the GM #1111258 distributor was even released).

[Michael H.]

Re: vacuum advance for 1111258 TI

If indeed this is the case, I'm truly surprised that I've never found a 201 on any 258 distributor. I've owned several all orig 435's and restored several more (real ones) and I know for certain that I would have noticed a 201 as that's a tough item to find for 63. Anything is possible though.

What are the other sources that you mention? I know I've never seen this number in any GM doc's. I think I have some Delco info from that era and I believe it mentioned either the 355 or 360 but not sure which. I do know it wasn't the 201.

If you look at the units listed in group 2.410, I think you'll agree that there are actually two possible correct units for the 390 HP 427 in 67. I believe one is listed as 65-66 with Sp. H/Per AND 67 427 with 4 bbl. The other is listed as 66-67 exc Sp. H/Per. It doesn't make sense that the 427 390 is listed twice.

Doesn't ANYONE have an original 258 that can provide some info on this???

[Michael H.]

Anyone Have A 67 Service Manual......

...handy that has the specs for the distributor/vac adv unit? Should be in the back and list the degrees of the unit for each distributor. Just wonder what it shows for the 1111258 distributor? Thanks

[Wayne M.]

Delco Remy DR-324S-2 (Jan 1, 1968) says ...

it has the 1116201. Other Centrifugal advance spec's for 1111258 are: Start Distrib. 500 rpm, 0-2 degrees (distr.deg, not crank); 1900 rpm, 14-16 deg; 3000 rpm, 12.5-16 deg.

[Joe L.]

Re: vacuum advance for 1111258 TI

Michael-----

Well, one source is Colvin's "Chevrolet By the Numbers". A chart in the distributor section of this publication states that the GM #1111258 distributor used the GM #1115201 prior to 7/66 and the GM #1116201 after 7/66. There never was any GM #1115201 that I can find (although it's possible that it existed as a PRODUCTION-only piece). Colvin's information came from GM sources; I don't think that he made any of it up himself.

In any event, Colvin's information regarding the 1111258 distributor's vacuum control is consistent with some other old GM information that I have. It's quite possible that both sources are inaccurate. I have no way of verifying it beyond the information that I have.

I do know that the GM #1116201 vacuum control was used in PRODUCTION through, at least, 1971 for some applications and it may well have been used later than that. However, as I mentioned, it was discontinued from SERVICE in January, 1965 and replaced by the GM #1116163. Both of these controls have identical (or near-identical) specifications.

If any other vacuum control was actually used in PRODUCTION for the 1111258 distributor, I would expect it to have been the GM #1116163. That's the one that Delco parts information dating back to 1968 specifiies as the correct SERVICE part for the 1111258 distributor and is the part that replaced the 1116201 for SERVICE.

Also, regarding the P&A Catalog references that you mentioned, there is information in the catalog which defines which distributors that each application listing applies to. These are as follows:

"ALL, Corvette (427)(exc. Sp.H/Per.,A.I.R., T.H---w/1111100-12-17-40-41-42

"66 PASS. (396 (exc.P.G.,T.H.)"
"66 PASS. w/Sp.H/Per. (427) (exc. T.Ign.)"
"65-66 CORVETTE w/Sp. H/Per.(396,427)"
67 CORVETTE w/4BC (427)"--------------------w/1111093-1247-48

So, the 1111258 distributor is not mentioned for either of the above references. Therefore, I conclude the application was omitted.

[Michael H.]

Re: Delco Remy DR-324S-2 (Jan 1, 1968) says ...

Thanks Wayne. I'm assuming the last part is 16 deg at 12.5" for the vacuu advance. That does sound correct for a 201 unit, unless it's 12.5 degrees @ 16". Very interesting.

[Michael H.]

Re: vacuum advance for 1111258 TI

I agree. I couldn't find the 258 in the parts book list for either the 355 or the 360 advance unit. The 1111258 isn't mentioned at all. I also looked for an 1115201 without success. The only 201 I found, even in old history, is the 1116201.

I have to assume that the 355's and 360's that many of the original 258 distributors have are actually replacements from years ago? I suppose that is a good possibility, especially due to the fact that a parts man in the 60's or 70's would be unable to find the 1116201 in any parts book at that time. Interesting. The learning never ends.

[Duke W.]

I quoted the vac can specs from the AMA specs...

...didn't you see. In fact, I think I quoted them twice... same as '63 down to the half-inch, which is the only time I've ever seen a vacuum can spec quoted at xx.5"

So what vacuum can numbers have you observed on L-71s.

Duke

[Duke W.]

Re: Delco Remy DR-324S-2 (Jan 1, 1968) says ...

Your data (from the CSM?) doesn't jibe with the AMA specs for L-71

Centrifugal:

Start point: 900
Intermediate: "NONE"
Maximum: 30@3800

Vacuum (for the THIRD time in this thread):

Start point: 8"
Maximum: 15@15.5"

These vacuum can specs are IDENTICAL, repeat, IDENTICAL to 1963 engines, and I am aware of no other vacuum can nominal specs that specify max advance at 15.5"

There is no indication of revisions on this page, so these specs would have applied from first prodution and the AMA was a "living document" that was maintained as specifications changed through production.

The CSM was printed once and not revised, so any errors are still there and any changes are not reflected.

It's clear to me that the service vacuum advance controls for several engines are different that OE spec, which was probably just a matter of convenience, and there was no need to specify the same spec replacement part on non-emission controlled engines.

The 163 can nomimal specs are within production tolerance of the 201.

Duke