The Ford Barn - View Single Post - Help decipher GM distributor vacuum canister numbers

Kilohertz · 01-13-2021, 12:06 PM

Good morning fine fellows,

Been reading for a while now and have digested all comments. I'll reply chronologically..

Charlie, I think I accidentally ended up with a few VC1802 as when I made my vacuum tests yesterday I found 2 that started at 8"Hg and ended at 14-16"Hg even though they are marked with the factory markings, not NAPA. One was on the '72 350 unit which is currently in my flathead and is functioning, the other was from my '74 Pontiac 455. So those should be fine but thank you for the offer of yours.

Yes degreeing the crank pulley is on my list, but I borrowed my friends Snap-On variable timing light which should accomplish the same result, but might be more cumbersome.

Ron, thank you for chiming in with your expertise. Yes an AF meter has been on my want list for a few years now..one day, hopefully soon. I think I have located a 4bbl intake, waiting for my friend to go see him and determine what it is, another local flathead rodder friend has the Edelbrock 390 CFM carb on his '32 roadster and he loves it. I still like the "look" of dual 2bbls but it's all about what I can find locally. I'll contact Charlie about the stop mods.

Tubman and 40cpe, thanks! Yes I have visited the Corvette site numerous times and that is where I have found most of the original Delco info, and the excellent article by Lars Grimsrud.

And as for the adjustable vacuum units, it's a great idea, but I am hoping once I get this dialed in, I won't be monkeying with it again, (ya, right, we know how that goes) I have enough cans here that I should be able to find one that will work, and maybe incorporate Charlie's mods.

I need to figure out a shop exhaust system so I can run the truck for more than 30 seconds at a time, gets pretty thick in there. It's also freezing outside so any time with the doors open, takes a while to build up heat again.

Today's project is to figure out radial movement of the vacuum canister acting on the points plate so I can figure out the distance traveled per * of advance. Then I can build a stop for the canister and mount it in the appropriate location. Sounds like fun. I knew high school Trig would come in handy one day....40 years later.

Thanks everyone!

Cheers

01-13-2021, 12:06 PM	#14
Kilohertz Senior Member Join Date: Jan 2021 Location: Slightly left of Vernon, BC Posts: 155	Re: Help decipher GM distributor vacuum canister numbers Good morning fine fellows, Been reading for a while now and have digested all comments. I'll reply chronologically.. Charlie, I think I accidentally ended up with a few VC1802 as when I made my vacuum tests yesterday I found 2 that started at 8"Hg and ended at 14-16"Hg even though they are marked with the factory markings, not NAPA. One was on the '72 350 unit which is currently in my flathead and is functioning, the other was from my '74 Pontiac 455. So those should be fine but thank you for the offer of yours. Yes degreeing the crank pulley is on my list, but I borrowed my friends Snap-On variable timing light which should accomplish the same result, but might be more cumbersome. Ron, thank you for chiming in with your expertise. Yes an AF meter has been on my want list for a few years now..one day, hopefully soon. I think I have located a 4bbl intake, waiting for my friend to go see him and determine what it is, another local flathead rodder friend has the Edelbrock 390 CFM carb on his '32 roadster and he loves it. I still like the "look" of dual 2bbls but it's all about what I can find locally. I'll contact Charlie about the stop mods. Tubman and 40cpe, thanks! Yes I have visited the Corvette site numerous times and that is where I have found most of the original Delco info, and the excellent article by Lars Grimsrud. And as for the adjustable vacuum units, it's a great idea, but I am hoping once I get this dialed in, I won't be monkeying with it again, (ya, right, we know how that goes) I have enough cans here that I should be able to find one that will work, and maybe incorporate Charlie's mods. I need to figure out a shop exhaust system so I can run the truck for more than 30 seconds at a time, gets pretty thick in there. It's also freezing outside so any time with the doors open, takes a while to build up heat again. Today's project is to figure out radial movement of the vacuum canister acting on the points plate so I can figure out the distance traveled per * of advance. Then I can build a stop for the canister and mount it in the appropriate location. Sounds like fun. I knew high school Trig would come in handy one day....40 years later. Thanks everyone! Cheers Last edited by Kilohertz; 01-17-2021 at 09:33 PM.