Help with V6 Engine Suffix Codes

[JimmyS10]

Talk about frustrating! Anyone called GM recently? After an hour and a half on the phone with 6 departments I'm no further in my quest than I was earlier. Hopefully someone on this board can help.

I am in the process of building a hot rod 28 roadster. I've decided to use a GM V6 powerplant for a number of reasons. Anyway, I was able to pick up a V6 pretty cheaply. Before putting in the roadster I want to rebuild it. In order to rebuild it I have to identify it so I get the correct parts. Seems simple so far, right? Well, everyone wants the year, make, model and VIN of the donor vehicle. I tried to explain to GM that is what I am calling them for. If I had that, I wouldn't need to be calling. Anyway, the VIN would only be valid IF the engine was the original for that vehicle. So, I'm looking for info from some of you more knowledgeable folks. Here's what I have and am trying to identify:

GM V6 4.3 L 4bbl carb
Engine ID = T1121UTC
Block Cast = 10105867

I know T = Tonawanda Buffalo, NY
1121 = 11/21
It appears to be an 87-91 based on the casting number.

Can anyone help identifying this engine further? Thanks in advance.

[Captainfab]

I don't know of any sources for 4.3 V6 suffix codes. If you get the casting date off of the block that should be all you need to tell you the date of the engine and then you will know what year range of parts to order. Does this engine have a balance shaft?

[geezer#99]

Here's a little known source for your suffix code.
Appears to be a 1990 motor in a full size type truck.
http://www.lmctruck.com/icatalog/cd/full.aspx?Page=9

[b454rat]

Not with a 4barrell. That would be 84-86-ish.

[Keith Seymore]

Nicely done, geezer.

Jimmy - another quick sort would be carbureted vs fuel injected. Is your motor TBI?

K

[b454rat]

Should have stated, what does the casting date day on the intake? I’ve never heard of a carbed motor in 1990. Any competent machine shop should know how to rebuild it.

[95 S_Trucker]

Originally Posted by b454rat

Not with a 4barrell. That would be 84-86-ish.

All of the 4.3 v6 engines made between 87 and 91(casting number) were fuel injected, so someone swapped the carb on.

[Bigdav160]

I thought the only 4.3L with a carb were in Astro vans and marine powerplants.

Of course the old 229 was carbed.

[95 S_Trucker]

Originally Posted by Bigdav160

I thought the only 4.3L with a carb were in Astro vans and marine powerplants.

Of course the old 229 was carbed.

85-86 in the c/k trucks were carbureted.

[Bigdav160]

I was working at Oldsmobile at that time. We didn't see many trucks.
But I can't remember ever seeing V6's in square body trucks. Straight 6, yes

[Greenlee]

Originally Posted by Bigdav160

I was working at Oldsmobile at that time. We didn't see many trucks.
But I can't remember ever seeing V6's in square body trucks. Straight 6, yes

They did exist. I remember a neighbor who bought a brand new 85’ 2WD short bed that had a V6.

[JimmyS10]

Thanks Geezer. Great find. That said, I found another number cast on the passenger side of the motor beneath 15 layers of paint and crud. That number is K169. That, I interpret to be October 16, 1989. So late 1989 and stamped 1990. TBI most likely removed and carb installed would be my guess. Is my thinking correct? Thanks again everyone...Jimmy

[Bigdav160]

Pretty sure marine versions were carbed to the end.

But yes, throttle body injection was used in passenger vehicles 87 and newer