Decipher serial number

[davis911s]

Hi Guys

I have a 58 or 59 GMC Bus



Not sure exactly what year. Hoping you guys can show me how to verify through the serial number.

It is a model 9452
Serial number 89452606882
Engine number T329425

It has a Chev 350 in it right now, doubt it is stock.

Anyway. What year is it?

[1project2many]

Chevy 350 350 was not available until '67 so any numbers obtained from the engine will not help with the year of the bus. GMC supplied Pontiac V8's in most trucks (unless they had a six) although many of the bus chassis had Buick Nailhead V8's.

The "serial number" doesn't match the usual 55-59 truck VIN. Where did you obtain the serial number from on the bus? Can you get a picture?

[OrrieG]

The engine if its a SBC should have 3 letters after the number on the pad in front of the passenger head, like 999999 CTE. The first part matches the original vehicle vin, the last three are year and application specific. On the top of the block behind the driver head is the casting number and a date code. Date code has one letter and 2-3 numbers like C148, which would be March 14 1968 (or 78). Photos of the engine would help.

[davis911s]

Engine for sure is NOT stock. I knew that. The serial number comes direct from the ID plate on the firewall

[OrrieG]

Misunderstood, thought you were asking about the engine.

[1project2many]

oldgmctrucks.com has some information that might help, and the owner of the site offers to help with VIN deciphering on larger trucks. A bus would most likely have started as a "flat back cowl." See here: http://www.oldgmctrucks.com/page0010.html to understand what GMC believes should be in most serial numbers. You can follow links on that page to find 55-59 GMC information and to find a link to send email to the page author for help with large truck numbers.

Engine for sure is NOT stock. I knew that.

You originally said you doubted it was stock but by including the engine number it seems like you're asking for confirmation. Or is that not the number from the 350??

The page I linked to shows GMC serial numbers usually started with a letter for 55-59 trucks. If the first character is an "S" that would fit with traditional GMC coding. "S" was used to designate 1958 and 59 model year. Then the next four numbers are the series, 9452. The next six digits indicate the bus was chassis 606882 in series. If the first digit is really an 8 then I would assume, with no other information, the vehicle is a '58. Not very positive, I know.

With the HP and torque numbers found on the ID plate we could identify which engine was originally installed.

If you can find the original "parts identification plate" we might be able to identify other major components.

The numbers didn't contain a lot of information back then. The numbers you posted don't exactly agree with what's published. Ultimately there may be more guessing involved than you are comfortable with.

[dwcsr]

Originally Posted by davis911s

Engine for sure is NOT stock. I knew that. The serial number comes direct from the ID plate on the firewall

It may be the bus builders assigned serial number. Does it say GMC on the firewall tag? post a picture. It looks to me like an assigned number, GMC numbers have letters and numbers.

[davis911s]

Sorry for the confusion. I am new to the old bus world.

I originally thought the 350 was a rebuild,and maybe stock, but like 1project2many stated, the 350 was not even available when it was made, so that eliminates that.

I have heard many of these big vehicles may have come with a 6 cyl from the factory. I will be sticking with the 350 as it appears rebuilt, and they are easy to work on and get parts.


Here is the ID plate. It is on the firewall in the engine compartment.It is a GM plate. I don't know why it is showing upside down?



It may be an S as first digit, but looks way more like a complete 8 to me than an S

Thanks already everyone

[davis911s]

1project thanks for that link

It has link for Canadian vehicles http://www.oldgmctrucks.com/page0398.html

From that
8 = 1958
94= Series
52= Model
6= # of cylinders
06882= Vehicle #

So I know it is a 1958, the engine was originally a 6 cyl.

It makes me wonder how a 6 cyl would have ever pushed one of these big heavy busses around. Gearing must be incredible. I know the bus has a 2 speed rear end also. I will have to see how that works and get used to it too.

Thanks again for all your help already

[_Ogre]

It makes me wonder how a 6 cyl would have ever pushed one of these big heavy busses around.

gearing, gotta remember that all vehicles had 6 cyl motors prior to the v8
nice that it has a 2 speed axle, i had a 56 bus that had that; it would cruise at 85 mph with the bbc

[1project2many]

It has link for Canadian vehicles http://www.oldgmctrucks.com/page0398.html

I'd guess I better brush up on my Canadian!

It makes me wonder how a 6 cyl would have ever pushed one of these big heavy busses around.

My '36 Plymouth engine makes all of 82 Hp but it can propel the car to 60 mph without trouble. It just doesn't get there quickly. As long as max speed is relatively low the relatively high torque of the six will be sufficient. If you want an eye opener, look at the power rating for some of the early diesel engines...

[Softpatch]

Originally Posted by _Ogre

gearing, gotta remember that all vehicles had 6 cyl motors prior to the v8
nice that it has a 2 speed axle, i had a 56 bus that had that; it would cruise at 85 mph with the bbc

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My Viking came with a 292 has the dana 2 speed axle.
......... Sooooo your saying if i put a bbc in my truck i can cruise around @ 85 mph..
Instead of my 327 's 45mph @3000rpm I'm criusing now.?
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[dwcsr]

It was most likely a 261 in a bus

[OrrieG]

My dad and his hunting buddies converted this bus to a elk hunting rig. Had a 292 six and Hydro Trans. Got 4 MPG empty or loaded. Max. speed was around 50 but would climb a tree. Only had a single speed rear end and was originally used around Pendleton military base so highway speed was not critical. It is the vehicle I learned that GMC had positive ground after I hookup the new radio wrong. They built a 200 gallon gas tank that filled thru the original fill, was pretty amusing when they pulled up to Oregon gas stations and told the guy to fill it up. They called it "Big Urge" and it brought many an elk home from eastern Oregon. Other photo is my Dad christening it.

[DransportGarage]

OrrieG, here's to your Dad...

[tmoble]

yep, here's to your Dad.

Softpatch, I'm thinking you already know this but installing a big block won't change the RPM. It's just that a modern V-8 would be more comfortable cruising at 300 or 3500. Lots of gas stations where you live?

[1project2many]

OrrieG, very cool to have pictures like that. I work on school buses daily and I am amazed at how small the front windshield is on that bus compared to today's buses.






Softpatch, you could try to find a heavy duty 5 speed trans with overdrive to lower max rpm.

[_Ogre]

Originally Posted by Softpatch

.
.
My Viking came with a 292 has the dana 2 speed axle.
......... Sooooo your saying if i put a bbc in my truck i can cruise around @ 85 mph..
Instead of my 327 's 45mph @3000rpm I'm criusing now.?
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.

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.
.
.

again, it's all in the gearing
thing nice about the 454 bbc is i could shift into 4 low and climb west out of denver at 65 mph
pretty impressive if you know the hill

it got 8 mpg and we eventually drove it coast to coast and border to border
we bought it for our 3 month, 10,000 mile honeymoon trip (1250 gal of gas)
lived in it while building our first home in nc, my oldest was born in it
last trip we took before selling it was 9000 miles in 29 days, just visiting friends and relatives

i was befuddled by the filler neck on the pass side in that pic
until i realized it was taken in your mirror

[Softpatch]

davis911s
Sorry I don't mean to jack you thread....

Orge
..........Your statement got my gear's turning .
I do have a spare 454 in the garage and thought maybe this would give me a bit more
then my tired ol 327 @ 3500rpm it seem at the end of the power band.

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I just change out a 350 to a 396 4spd with 410 rear in another car and
could not tell the different.?
only that the 350 got up faster then the 396 that could be cam timing issue.?


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Orge
You are correct pic out my driver mirror
watching for any flex in the rear leaf spring
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[davis911s]

Softpatch- no prob at all. I got the answers I was looking for and love hearing about other projects. Thank you!

[_Ogre]

it's all about gearing, a motor swap will not increase speed
i have no idea what gears were in that rearend

[OrrieG]

Rpm is a factor of bore and stroke. Your tired 327 will out rev the 350 or 396 given equal camming. The 327 has a shorter stroke. My experience with 283/327 engines is at 3500 with the right cam them are at the bottom of the power band and will easily pull to 6K+. Early SBC had smaller journal crank, with less rotating resistance, that built right could go much higher RPM.

I was disappointed to find the 350 I put in my Chevelle, which has a mild cam runs out of steam at 5500 but does have a lower power band.