Had the vette for a year. Advertised as a 350. I knew the numbers didn't match. $7000 i paid. Mostly needed some interior work. looked and ran great! I decided to check the numbers because I'm looking at a water pump. This is what I have.

TH400 Transmission no concern because I have a 200-4R on the way.

Engine stamp(s) - T0525TBC & T9S527321 ...yes two stamps which is standard I suppose. These codes are on a square block on the passenger side above the water pump.

I used this site:
http://www.nastyz28.com/gm-chevy-cod...s-suffix-6.php

From my understanding one is a partial VIN and the other is the Engine Code. Looking at this site with the "T9S" prefix tells me that its a 305. but the "TBC" says its a 350 from a 1970 C-10 to 3500.

I really don't understand the correct way to decode these numbers. RPOs and Partial VINs have me lost because I don't exactly what the engine came from, not even the dude I got it from.

Does anybody know of this area better that me?

 

TBC is what you want.

First because the pad is square it's a late 70's block. You will notice one listing on the site for a 79. That appears to be what you have not a 70.

 

TBC is a 70, 71, or 79 350CID truck block assembled at Tonawanda on May 25th.

T9S527321 should be the VIN derivitive of the original vehicle the engine was installed in. It could be I9S (or 19S) and might have come out of a truck or van assembled at St. Louis.

 

So the RPO is the last 3 characters of the code? And what does the acronym "R.P.O." mean?

What about the other code? It must be a partial VIN,...right?
Ant way to decode it?

 

Ok didnt see,your post Mike. So I have a 350 LS9 with only a measly 165 HP? WTF. Now I see that the tranny went out. The dude swore it had 280 HP because of the mild 274 cam and 373 rear. Oh, and he had a 750 CFM carb, which I replaced with a 600 cause it ran really bad. He was ******* the car like he was ready for the track.

 

Yeah guys Im mad. and Im thinking like what the hell did he think he had. I was in a buddys vette that was dyno'd at 492 HP and I was scared. now im realizing that my lil engine only produced a fraction of his even at the Fairy Tale Story of 280 HP. Damn It

 

it is pretty simple, look at the casting date on the block, should be back behind your distributor on your bellhousing flange.. this will clarify alot.


gee... nobody ever looks at the dates when this will really narrow down what you have.....

 

here is what I have behind the distributer:

On driver side:

43GM

14016379

On passenger side:

D 2 A 9

 

The codes only reflect what the engine was back when it was built. That was over 30 years ago. No telling what's in it today.

If you're mad- it should be at yourself for not checking things out before you bought.

 

You have a 350. It is not an LS engine.

RPO stands for Regular Production Option. Your TBC is the engine identification suffix; it is not an RPO number.

 

Huh Easy Mike? The list states 1979, L LS9, 165 HP. What did I miss?

 

You need to follow the column up where it states L LS9 and you will see it designates these characters in the "VIN", not in the engine suffix.

When it comes to an engine designated LS9 this would be nice: http://www.autoblog.com/2009/02/19/l...han-most-cars/

As stated that is what the factory produced and who knows what someone has done to the engine. You might have 280hp. Only way to find out is a dyno to set your mind as ease. Good luck.

 

Where does your list come from?

LS engines are the new model small blocks in use today.

The older LS series engines were big blocks.

TBC identifies a 350CID small block.

 

I feel like a dummy saying I have a LS9 engine and don't even know what THAT really is. Y'all are great and extremely helpful. And this all came up because im looking at converting to a serpentine setup.

 

Yeah mike when I saw LS9 and the data that followed, I assumed it was an older engine...

 

Easy mike, The list I found was on nastyz28.com. refer to my first post.

 

I went back and looked at the list on the link. I see where the LS9 has come from. I did not use the site in the link when I posted; I used the Lime Book.

The Tonwanda engine assembly plant built big blocks and small blocks. All Corvette big block engines came from Tonawanda. All the small blocks came from Flint.

Some of the Corvette big blocks are designated LS. I do not know truck blocks, but it could have been possible that some of the Tonawanda small blocks used in trucks could have been LS, but that was 20+ years ago.

The current LS series small blocks are the new generation of GM engines. C6s have LS engines.

 

The LS9 name is simply being recycled. It was previously used in the 70s as an RPO code for low perf truck and SUV engines.

 

Thanks all. I'm just gonna continue with my upgrades.