Mystery option Vacuum Gauge?

[Skip Greaney]

I am going to have chipflyer redue my spid for me but there is one line I can barely read. It looks like Vacuum gauge which I know was an option, but I never saw it on a 1ton down truck only on C40 and above. Any one know of a vacumm gauge on a C10, C20 orC30? This is a 1970 Longhorn CST. Option letters look like 4J8LAD, but cannot be sure! Tach dash is not it truck only the usual 3 guages so no way to confirm but I can read 4U16BA Tachometer option clearly.

[674x4ton]

Got any pictures?

[special-K]

I think that "L" must be a number.For instance,I believe the three digit code for tach is "U16". Once you figure out what that code is you will have your answer,at least on your truck. If your SPID has vacuum gauge and corresponding code than you will have answered this question for all of us. The school of thought at the moment says the vacuum gauges were not offered on light duties.

[Skip Greaney]

I would take a picture but it would not come out as this label has overspray from it's journey from Gold to Brown :-(

I am using a magnifying glass to read 3 lines out of 26 in the middle of the label. So here is the middle of the label and I'll take the best guesses. The (?) represents an illegible Charecter

4F51AE- FRT & Rear Shock AB 4F54A?- Front Stabilizer EQ
4F60AC- Heavy Duty Front SP 4G60A?-Auxiliary Spring EQ
4G86AL-No Spin Rear Axle 4J70DE-Brake Booster Equip
4J8?A?-Va????????? 4K31AA-Manual Throttle
4K05AA-Engine Block Heater 4L47AT-400 CU. In. V-8 Engaps
4K76BB- 61 Amp Delco Genera 4P03AC-Chromed Hub

There is more above and below this but all is legible! Best Guess?!!!

[Skip Greaney]

Down at the bottom of the label it reads 4U16BA Tachometer, and I found the tach harness cut, but still there. The tach dash is gone and only the 3 gauge cluster is in it's spot. I do not see a vacuum hose of any kind under the dash.

[bruceman1968]

J80 : VACUUM POWER BRAKE RESERVE TANK or
J81 : VACUUM GUAGE EQUIPMENT
These are both from chipflyer's website, looks to be the only two possibilities

[special-K]

I believe you do have proof that vacuum gauges came in these trucks. This computer screen is off since it got fixed and I couldn't see the codes in the left column on Chipflyers site. But,I figured the "L" could only be a "1" since that digit should be a number. What year is this truck? It's a C/20,right? I know the heavy one tons (wide-5 front/10-lug rear) could have a vacuum canister under the cab with a breather up through the floor at the driver's side rear corner for a heavier brake system. You seem to have the extra vacuum component which would give cause to having a vacuum gauge. There was no real need for a vac gauge with normal equipment on light duty trucks,which is why a gauge would not have been offered. I'd like to know all the info you can provide and most definitely see pictures. Do you have a breather cap through the floor or an extra brake booster mounted other than at the firewall?

[chipflyer]

As stated above it is J81 on the vacuum guage. I would like to see a picture of the original SPID, do you mind posting a pic of it? That would be the first original I have ever seen with the vacuum gauge on it and I still say it wasn't available on a C10 or 20 until I see an original spid with it listed.
To the best of my knowledge know one has ever been able to explain the last to letters (or possibly numbers) if they are even there. Pick a letter on yours, its doubtful it would ever be proven wrong. No doubt they meant something, I am just afraid the info has been lost and we will never what.

Jeff

[Skip Greaney]

This is a C30 not a twenty. I had a C20 back in the day with a lot less equipment, and this one looks the same. No extra boosters or vacuum equipment that I can see. It was also a Big Block and I see no diffrence in this truck than that one. Other than A/C and camper stuff on this one. It came from Oregon/Washington. So I can read for example
4VK2AG Tool & Storage Box even though that is also gone. So there are some lines that have 2 letters and a number instead of a letter and 2 numbers which is why I thought it might be an L instead of a 1. If I had to guess. It is not a zero. I can see that much. The line is straight not curved.

[special-K]

I asked if it was a C/20 because I saw it couldn't be a C/10 since it has the No-Spin option. I thought to say C20-30 but didn't. Now that you mention it,that is true about the letters in the second digit. I still have the glovebox door from my old Custom Camper and it looks like the tool & stowage door,camper wiring,and camper mirrors all have two letters and one number. So does the engine code for that matter. It's the 2nd,3rd,& 4th digit that really matters.
I have a heavy one ton cab here that had that brake set-up that had a breather up through the floor. It had the medium duty lug pattern and 18" wheels. It is a '69 short wb cab & chassis. There is no mention of vacuum gauge,brake equipment (not even power brakes) or anything in the model number that separates it from any other C/30 short wb cab & chassis (model # CE31003) except the H22 axle option.

[Skip Greaney]

The model # is very legible CE31034. No breather or anything coming through the floor. I will see if my camera can get a picture. As I said it is a paper spid not with plastic over it, and the previous owner/s painted everything brown. Dark choclate brown which will require a large amount of time to strip off to repaint. I have acquired every option the truck has, or has missing like the A/c brackets, the spacer air cleaner and the very hard to get heat shields and heat tube up to the air cleaner. The tool box though it needs alot of work, the throttle label and both kinds of pedals and bracketry. But I cannot figure out what this thing is because I cannot read it. I am a Service Manager for a large Chevrolet Dealership so I have a lot of resources and a former technician from 1978-1993 so I worked on a lot of this stuff. But I never saw a vacuum gauge on a 10-30 only governed 40-70
series gas trucks. But this truck has a most options I have seen on a 1970 model. The 72's had more, but this is a weird one.


Skip Greaney
1970 C-30 CST Longhorn
2004 Chevrolet 2500 Suburban 8.1 4X4 LT (autoride)
2010 Cevrolet Corvette Grand Sport
1996 Harley Road King
1990 Jaguar XJS V12

[Skip Greaney]

Also I type like crap...miss the occasional letter like Chevrolet, not Cevrolet!


What a spaz!

[special-K]

Oh, I thought maybe GM was starting to come out with some new divisions again and maybe Cevrolet was to Chevrolet what Scion is to Toyota or something. (actually,I didn't notice it was wrong...I read like crap)

Here's that breather in the floor. This truck had the 11,000# axle option:

[Skip Greaney]

Yeah I have seen that but not on this truck...I guess it will remain a mystery. I see some of the replacement clusters have Tach and Vacuum, but I always assumed that was just some folks customizing that empty spot. I did see a chipflyer recreation that had a vacuum gauge, was that on the spid or added for owner taste? That might answer if it was possible. Because this truck is so heavy duty, and so well optioned I am going to assume it is a factory installed option.

[chipflyer]

It was the owners taste Skip. I always try to discourage people from using things that don't belong but some just don't care, they want it on there and are willing to spend the 3 bucks to add it. I have kind of become tired of fighting people on certain things and that is one of them. I can make a label that looks exactly like the originals but if we put things on it that didn't belong we might as well use a blank label and a crayon and save a little money.
Although I am not 100% sure on a C30, I still do not believe it was ever an option on the C10/20, but I will change my mind if someone shows me an original label with it on it and gm documentation that backs it up.

Jeff

[Skip Greaney]

Here is the best picture I can take with my camera! Sorry I told you it was hard to read!

[tcb-1]

the spid says that it's a 1970, 1 ton with a V8 built at the Flint MI plant, optioned as such:

body type #
body side moulding
air conditioning-ac
front and rear shocks
heavy duty front springs
no spin rear axle
engine block heater
61 amp Delco generator
power steering
camper wiring
tachometer
rear step bumper eq
white/med gold/white
tinted glass
door edge guards
camper mirrors - stain(less)
front stabilizer eq
aux springs
brake booster eq
manual throttle
400 cu in V-8 eng
chromed hubcaps
marker lights
tool & storage box
custom sport truck
gold vinyl custom

what am I missing? where's the vac option????

[bruceman1968]

Doug, how about k76 61 amp delco for where you have a question mark. also here is a trick I sometimes use. It work sometimes and sometimes not. open the pic in paint and hit invert colors....works sometimes....

[tcb-1]

yep Bruceman, inverting the colors does work great.

I'm on my wife's Macbook tonight and I was able to do a bit of Apple magic on it to read it.

[chipflyer]

Below is what I came up with Skip, some of the codes last 2 characters I couldn't make out but found them in my collection of 1970 labels. As Doug mentioned this label has no mention of the vacuum gauge option on it so that search must go on. It is a very nicely optioned old truck though.


MODEL # CE31034
4A11AA TINTED GLASS
4B85AD BODY SIDE MOULDING
4C60CV AIR CONDITIONING -AL
4DF2AD CAMPER MIRROR -STAIN
4F51AH FRT & REAR SHOCK AB
4F59AA FRONT STABILIZER EQ
4F60AB HEAVY DUTY FRONT SP
4G60AH AUXILIARY SPRING EQ
4G86AL NO SPIN REAR AXLE
4J70CX BRAKE BOOSTER EQUIP
4K05AA ENGINE BLOCK HEATER
4K31AB MANUAL THROTTLE
4K76AV 61 AMP DELCO GENERA
4L47AT 400 CU. IN. V-8 ENG
4N40AL POWER STEERING
4P03AC CHROMED HUBCAPS
4UY1AD CAMPER WIRING
4U01AA MARKER LAMPS
4U16BA TACHOMETER
4VK2AB TOOL & STORAGE BOX
4V43AA REAR STEP BUMPER EQ
4Z84AA CUSTOM SPORT TRUCK
4584AA WHITE/MED GOLD/WHT
4625AT GOLD VINYL CUSTOM T

Jeff

[Skip Greaney]

Right below Gold Vinyl it says something. I don't know what. If you look at my photo right below the 6 and the 2 you can barely make out what I'm looking for. With the blue one...very cool by the way I cannot see it. Also way down in the lower right corner it says something that I also cannot read. But I'm told that is some special number the factory used. The clearest charecter is right below the 2 and it looks like an 8 under a magnifying glass.

[Skip Greaney]

I am OK with what you have Jeff, I can read most of that. So I'll probably go with what you have. We'll talk tomorrow and square a way the payment. My eyes are crossing trying to see whatever this is, so I'm hanging up on this for the night.

[chipflyer]

I kind of see what you mean Skip but I can't make it out and don't know what it would be or why it would even be there after the last option. The vacuum gauge option, if it were really on the label is J81 or 4J81XX in this example and it would have been found alphabetically between "auxiliary spring eq" and "no spin rear axle".
I am pretty much bug eyed now and ready for bed after looking at this one.

Jeff

[bruceman1968]

Doug, I should have known better Apple magic is even better than Disney magic..


Skip, That's a nice truck you got there. I mean really nice, CST, lots of options, real nice. Who ever was drivin it back in the day was the king of the jobsite for sure.
That might be the original factory dash, I saw a pic in your other thread. Is the back punched out for a tach? If so, and with the cut wires, someone probabilty robbed the tach before you got it.
Also I noticed you and I are in the same area. If you ever need anything checked on around here let me know. Always happy to help. Im in Dunedin/Clearwater area. There's a Chevy/GMC truck yard in Pinellas Park called Dennis truck parts that has a lot of 67 to 72 stuff....http://www.dennischevytruckparts.com/ ...once again REALLY NICE TRUCK....Bruce

[special-K]

Would one of you go to Dennis and ask him whatever became of the molds for the tool & stowage doors he was making from fiberglass (or other composite?)? I think they were ahead of their time and would sell for double what he asked back in the late-80s/early-90s.