Hi, I bought a 1970 El Camino SS 396 that has had the big block removed and replaced with a small block 350. Is there any way to prove that it ws a big block car? I don't have the build sheet, but I do have the protectoplate. Is there any information on it that would tell me? Thanks, Mike.

Yes, the engine code is on there.

If you post the POP exactly like it appears, I can help you

You are looking for the engine code on the 2nd line, far left that would be like this example;

T0921??? (all 1970 up engines have 3 letter suffix, 1969 back had only 2)

T is the engine plant code for Tonawanda where all big blocks were made, if there is a F instead of a T, it was a small block and not an SS
0921 is the month and day
xxx is the engine code

The presence of a big block 396 is not an indication of a SS 396 as those were available w/o SS as LS3.

Thanks Mike, here is the POP as it appears:

136800L118011
T0905CTW CCW0919B 9
70F261 11331


Let me know what you think. Thanks for your help, Mike.

T0905CTW is engine code
T - Tonawanda Engine mfg plant
09 - Sept
05 - Day
CTW - 396-350hp L34 (SS396 base engine)


70F261 is TH400 trans code
1970 model year trans
F - 402/427/454 engine usage
261 - Date code

CCW0909B is axle code
CCW - 3.31 axle ratio non-posi (standard on SS option)
09 - Sept
09 - Day
B - 2nd work shift on that day built the axle

9 is the month the El Camino was built 9=Sept (fit with engine,trans/axle dates)

11331 are steering, brakes, AC and radios option codes

Wow, thanks Mike. What a great help you've been. I had a feeling it was a genuine SS and a big block car. The only thing that didn't seem to make sense to you was the 3rd character of the transmision code. I looked at it really good and it definitely is an "F", not an E, so I dodn't have a clue what that could be about. If you ever find out, let me know and thank you again ! Mike.

On the F in the Trans code, I found out more on it. I just did not look at it closely in my parts book.

F - 402/427/454 engine usage

E - Refers to 1969 396 usage

Note-While marketed as an SS 396, the engine was actually 402 cid starting in 1970

That sort of pulls it all together. It's one thing to think you know what you have, but it's great to "know" what you have. Now that I am sure of what I have, I am considering searching for a correctly numbered 396 and bringing the El Camino back to it's original glory. Thank you so much for your help. I appreciate it. Mike.