My radiator has a J stamped on the engine side of the top tank and D and C stamped on the engine side of the bottom tank.

Wondering if these mean anything? The J could be Julian for October, which would be correct. But the D and C, I have no idea.

Thanks a lot! :D

I have a Harrison rad (not from my car) from an automatic.

U P on top tank
D G on bottom tank

no finger guard, no radiator tag

Hmmm, the stampings must mean something ...

You are correct, they do mean something! With very few (if any) exceptions, all original Harrison tanks should have a 2-letter code on them. The top tanks will also have a smaller third letter in between the two larger letters. Discussion below is for 65-67, but would apply to 68+ as well (except of course it would be end tanks instead of top/bottom tanks).

If you think about how the Harrison radiator assembly line would have worked, each radiator was an assembly of several parts - a top tank, a bottom tank, a core, and a set of straps and mounting channels (and in some cases a finger guard). The larger letters are just the identification code for the tank itself. They are sort of the equivalent of a build-sheet code for the tank piece for the Harrison radiator assembly line worker. Since the same tank could get used on multiple different radiator applications, you can see the same tank codes on different radiators as long as the tank is the same (for example, all 66 3-row 396 radiators used the same top tank regardless of transmission), even though the part nos. and the Chevrolet build sheet codes for each radiator are different.

With that said, I have seen two 66 3-row radiators that did not have a visible top tank code (but did have the date stamp). They were both finger guard radiators, so perhaps the welding on of the finger guard obliterated the codes.

The smaller letter in the middle on the top tank is the date code for when the tank was stamped. It is the usual letter-per-month format, with the letter 'I' omitted (so M=December).

There is also a date code stamped on the mounting channel on the driver's side, which is typically the same as the upper tank date code, but sometimes is a month later. That one is either the date the channel was stamped, or the date of final assembly of the entire radiator unit.

So, if a car has its original radiator, the tank date code should match or precede (by no more than one month) the mounting channel date code, and the mounting channel date code should match or precede the car's body build date on the cowl tag (bearing in mind that a car with a 05D cowl tag date, for example, could easily have a E dated radiator that was assembled earlier that same month). And a radiator with a F dated tank and a B dated strap is most likely a hodge podge of parts from two different donor radiators.

Then there was the small metal tag attached to the lip of the top tank that you've all probably seen pics of, that has the Chevrolet part no. and Chevrolet build sheet code on it. So once the radiator was assembled at Harrison and shipped to Chevrolet, the tank codes were irrelevant to the Chevrolet assembly line worker and only the build sheet code on the metal tag mattered.

In rare cases (on original radiators that have never been to the radiator repair shop) you also see an additional very small metal tag attached to the lip of the top tank with another 2-letter code on it. Speculation by a couple of sources has been that this is the assembly date of the entire radiator unit, but no one to my knowledge has ever been able to decipher the coding (for example, I have seen AB and AH on production year 1965 radiators, and BG on a couple different 66 radiators. How that makes a date combination I just can't figure out).

I have been working on trying to accumulate enough data from enough verifiable original cars to fill in all the gaps to be able to list part no., build sheet code, top tank code and bottom tank code for all 66-67 396 radiators. Still lots to be pinned down, but I'll post what I have gathered already as soon as I can find it on the computer! Jeff

Thanks for that post Jeff, very helpful. :thumbsup:

Interesting, Jeff - thank you! :thumbsup:

My top tank had a U & P with a little G up and to the middle of the U & P. It's a three row with the slanted fill hole on the drivers side and the inlet also to the driverside just to the left of the fill hole.

The bottom tank has a L & Y, it is for a manual transmission with no holes for the transmission cooler, outleft on the passenger side and drain cock on the passenger side.

Never knew about the date code on the mounting channel. I have a F there. I would guess that a F on the mounting channel and a G on the tank would be OK for dates.

The metal tag is long gone; but I think it is suppose to have a VX on it.

My top tank had a U & P with a little G up and to the middle of the U & P. It's a three row with the slanted fill hole on the drivers side and the inlet also to the driverside just to the left of the fill hole.

The bottom tank has a L & Y, it is for a manual transmission with no holes for the transmission cooler, outleft on the passenger side and drain cock on the passenger side.

Never knew about the date code on the mounting channel. I have a F there. I would guess that a F on the mounting channel and a G on the tank would be OK for dates.

The metal tag is long gone; but I think it is suppose to have a VX on it.

That's a good one for reference then if it still has all its original parts. The F (June) on the channel preceding the G (July) on the tank means that the F has to be the channel manuf. date and not the overall radiator assembly date (which would have to be July or later). That lends support to the theory that the little tiny 2-letter tag is the radiator assembly date. Now if someone can just figure out how to decode that little tag we'll be in business!

Jim, what is the cowl tag date of your car? Also, does (or did) your radiator have a finger guard? It should if it was a VX build sheet code. VZ is the build sheet code for the same radiator (3-row manual) without finger guard (for the AC / A.I.R. / H.D. radiator application that used a fan shroud).

Jeff