Hello and thanks in advance

[cmcnally2]

I am hoping you can help a new guy here, i bought a 1954 GMC truck with a transplant SB Chevy & what i believe is a TH350 auto. I am hoping you can help me determine what exact motor/HP is in it. the numbers that i was able to see are:
BLOCK #3970010
ENGINE CODE #V1126CMD
PARTIAL VIN #12L116798
so far I believe it is a 1969-1979 350 but if anyone can help with more info it would be greatly appreciated

Thanks in advance!!
Chuck

 

[ChevyHiPro]

Hello and welcome to the forum!
From the Block Casting Number you posted, 3970010; 1969 - 1979, 302/350 CID, Car & Truck, 2 & 4-Bolt Main, 4 Bolt Most Common.
This Block Casting number is one of the most common ones seen.

From the Engine Assembly Code, V1126CMD; V = Flint, MI (engine assembly plant), 1126, (date code) November 26, CMD (engine suffix code) 1974, 350 CID, turbo 350 (trans), taxi, 2 Bolt Main, A body (full size car).

So, from the Engine Partial VIN Code, 12L116798; 1 = Chevy, L = Van Nuys, CA (vehicle assembly plant), 116798 = last 6 digits of the vehicle VIN number (matching numbers!).

I hope this info is of some use to you.
Don't be a stranger around the forum, stop in from time to time and let know how your doing on your '54 truck build!

 

[cmcnally2]

Thanks for the info so it looks like a 2 bolt 350 out of a 1974 taxi whoo hoo! I certainly will stick around I am sure that I will have more questions

 

[ChevyHiPro]

cmcnally2 sez, "so it looks like a 2 bolt 350 out of a 1974 taxi whoo hoo!"
:lol:

Yeah!
That's what the numbers came up with!
So, I'm thinking, we change your forum name to "Habib, The Taxi Driver"!
What ya think??


What I've always thought is; what it was, where it came from, just interesting conversation.
I can tell what it is, just by checking a few things on the engine.
What's of more importance is; what I'm going to make of it!
So, it's a pre-86 350, OK, I'm going to bore it 0.060", put in a 400 crank rotating assembly, mild popup pistons, a real grunt adding cam (torque), free flowing heads with about a 65 cc chamber, make about 9:1 compression, flame throwing HEI distributor, 750 cfm carb (probably Demon) on a dual plane torquey manifold, try to get all the HP to the rear wheels by putting on an electric water pump and electric fans on the radiator, then slip a 100 HP wet NOS shot assembly under the carb, strap on a pair of free flowing, scavenging headers and X pipe exhaust out the back.
So, I got about $3000 - $3500 in the engine, it puts out close to 500 HP on pump gas (uh, premium), close to 600 HP on juice and the torque numbers will look like the national debt!
On gas, 550+ ft/lbs, on juice, +675, if not 700 ft/lbs.

The smile on my face, priceless!

Call me Habib, paint my hot rod yellow, but smile when you do it!!
:twisted:

Yeah, like that!
That's what I'm talking about!

So, who cares what it was!??

 

[cmcnally2]

I agree, interesting to know where it came from, the motor runs great now so I won't be putting any money into it at this point. not looking to make huge HP as my ride is just a cruiser, no need to burn rubber. like you said who cares what it came out of, if it was a corvette it would most likely be lower milage but highly abused, a taxi high milage well maintained who knows it is all a crap shoot. all I really know is that it currently runs good

 

[ChevyHiPro]

There's not a thing wrong with the 2 bolt mains 350's.
A whole lot of those motors have been used in circle track racing and on the drag strip.
That 2 bolt lower end will easily support up to 500 HP with no problem.
Stock or aluminum connecting rods are only good for about 425 HP, they'll break before the mains give way!
Seen it before!

In my experience, these modern engines with reasonable care, will run +200,000 miles. If one keeps a car that long.
The electrics in the car usually start going bad after about 10 yrs or so, that's time to get rid of'em!

For years, I've built and rebuilt Chevy small blocks for my use, to sell and to hot rod.
At present, I have 5 SBC's in my shop, two on engine stands, ready to go, a 383 stroker and 355 (350 bored 0.060"), two '81 and earlier 350's that need rebuilding and a totally worn out '85 305 to build up.
A couple of them to sell, the others are going in street rods I'll be build over the next few years.
It's not a business, it's a hobby for me.

If you can come up with a little extra cash, and a weekend to work on your truck, a really good upgrade would be to swap out the TH350 for a 700R4.
I think the 700R4 came out in the early '80, so finding a serviceable one in junk yard shouldn't be hard and not expensive.
That transmission is a four speed with overdrive.
It is also a 'stronger' transmission than the TH350, or TH400.
The 700R4 is about 3" longer than the TH350, so the crossmember under the rear of the transmission will probably have to be moved back.
Later model frames would probably have the necessary holes in them, but a drill and bit and you can make the needed holes in a few minutes.
So, the drive shaft would need to be about 3" shorter as well.
Measure your shaft before you head out to the junk yard and you should be able to find a shaft there as well.
The 700R4 will give you much better gas mileage and a lot less trouble than the TH350.

I hope you have many easy cruisin' miles on your Taxi Engine Habib!


Keep us posted on how you're doing with your vintage GMC truck!