1965 L78 Vacuum Can

[Joel T.]

Re: 1965 L78 Vacuum Can

Now you finally tell us it doesn't have an OE cam. Why does it take guys 20 posts before they finally explain what they have.

If you have a non-OE cam use the Two-Inch-Rule to determine what VAC to use.

Duke

Duke;

You are right... I apologize for not posting that fact sooner. I thought I mentioned the non-OEM cam in an earlier thread.

At this point the B28 VAC gives me partial throttle detonation as you mentioned, even with the basic timing retarded by 4 degrees so I guess my best course of action will be to reinstall that 355 VAC and advance the basic timing up a couple more degrees (like to 12-14) and see how it performs. It may be marginal from the two inch rule perspective but hopefully the detonation issue will go away.

Thanks again, I appreciate your help.

Joel

[Duke W.]

Re: 1965 L78 Vacuum Can

Maximum WOT advance for a big block should be in the range of 36-40, so you should not advance the initial timing beyond 10.

You can try reinstalling the 355, but bump the idle speed up until it pulls about 14". The 355 should be at full advance at about 12", so yours might be a little tired. Buying a new B20/26 might be a better idea.

Duke

[Carl N.]

Re: 1965 L78 Vacuum Can

I adopted mine in 1971 and believe it to be original with a 355 - mid July build date.

Carl

[Bill W.]

Re: 1965 L78 Vacuum Can

Sorry to take so long Im just getting back to the board. 65# 16120 has dist 093 with a 355 vac.

[William D.]

Re: 1965 L78 Vacuum Can

Car number #21326 built July 1, 1965 has a 360 12 vacuum can on it. I believe distributer original to car.

Bill

[Gary C.]

Re: 1965 L78 Vacuum Can

Gents,
Do you think think the issue raised here with the model number for the L78 canister (201 or 355) should be added to this thread regarding the next revision of the JG for 1965?

https://www.forums.ncrs.org/showthre...-Judging-Guide

My L78 has a 355.

Cheers,
Gary

[Roy S.]

Re: 1965 L78 Vacuum Can

Guys, not trying to be stick in the mud here but please realize, NCRS does not have the manpower to monitor the discussion board and pull off discussions about part numbers and what should or should not be in the judging guide. Simply does not/cannot happen given our organizational structure and volunteer system.

If you have a suggestion for the 1965 Technical Information Manual and Judging Guide I suggest you send it along with the supporting documents to the Team Leader in this case Elio Martin, Elio and Mike will have a working relationship that might allow sending it to Mike since he is the former team leader. Posting it on the discussion board is not a guarantee it will make it to a manual.

Recent information sorted and organized by Bill Clupper, past president, and past judging chairman indicates that indeed GM part #1115355 which is referred to as 355 because of the way it is labeled, is correct with respect to Delco distributor vacuum advances for the L78 and several other engines.

[Gary C.]

Re: 1965 L78 Vacuum Can

Roy,
I understand what you are saying but all as I am trying to do is build the list with informed input from the discussion board and then send it to Elio & Mike for review proir to the revision of JG.
Cheers,
Gary, Perth Australia

[Roy S.]

Re: 1965 L78 Vacuum Can

Gary,

I have no problem at all with you doing exactly what you are doing. My point was for everyone’s sake simply posting it on the discussion board does not get the job done! It has to be forwarded to the team leader, and there has to be supporting evidence, at a minimum. The volunteers that produce these manuals are not expected to and do not have the time to monitor the discussion boards.

[William C.]

Re: 1965 L78 Vacuum Can

I am currently researching all available materials in my library to get together a comprehensive list of distributor/vacuum advance matches for as many years as I can. I'm currently working in the 75-76 era, and moving newer as I go on. I have found the Gm parts books of the era ( at least the ones I have) to be at times incomplete or incomprehensible in the late 70's but other sources are available. When I've gotten as far as I can I'll send the info to Roy and Mike for review and dissemination to the teams.. No wonder I stayed away from the 75-up cars all my life until the C-4 came out!