Radiator part # and date codes for 77 TA/SE

[JDMopar]

I need to get a radiator recored for our 77 Trans Am SE. Will the original radiator have the same part number as a radiator from a 79 Trans Am SE? I have a 79 parts car TA that the radiator is loose and easier to get to than getting the one out of the TA I'm going to start the restoration on soon. I have a good radiator shop that will Recore it for me with a higher flow core than original, and I want to go ahead and get it done before the EPA finds this place like they did with the excellent radiator shop that was closer to home. I know I could buy a new aluminum radiator cheaper than redoing an old one, but I want this car to look like it did the day it rolled off the truck at Harry's Cadillac-Pontiac when it was new. If they are date coded, I don't mind pulling the original radiator out of the 77, even though it won't be as easy.
  I appreciate y'all putting up with my dumb questions! I've got 48 years of info in my head from fooling with Mopars, but GM and Chrysler may not have done some things the same way. I just want to make everything on this car as right as I can while I'm the caretaker of it. I will take a few liberties like a Holley Sniper EFI system and either a 700R4 or a 200R4 trans, but that's about it.

[firebirdparts]

I have a parts catalog printed September 1979, so that's probably about as good as we're going to do.  Obviously it matters a ton that the 77 is a 400 and the 79 is an Oldsmobile 403.  I'm assuming here.  There is a matrix of radiator options:
Automatic vs. manual
A/C vs. Not
HD cooling option.  for some reason this is a really common option in GM for a long time.  I think it was just a way for the dealer to make $10 more, I don't know.

What I see in the parts books is yes, they're the same if the cars are relatively similar and the Olds 403/Pontiac 400 is the same.

The radiators are labeled with a two letter code.  These two-letter codes are on the trans cooler (passenger) side tank, facing the engine, on a big tag.  Big letters.  76-79, the codes are the same, but multiple codes could direct you to one replacement radiator.  I think for replacements they maybe substituted a little bit.  Maybe.  You can have the shop move that tag if you need to.

These codes are in block 45 of the build sheet.

[firebirdparts]

So for instance:
1977 4 speed with a/c is FD
1977 Auto A/C is FD

1979 auto a/c is commonly FO
1979 auto a/c HD cooling is FU

FO and FD gives you the same part number as far as a replacement goes, which is 3031059  Originally, they must have been some tiny difference. 

[JDMopar]

 What a great reply! I am pretty sure the radiator in the 77 TA/SE I will be fixing is the original, so I will get under the hood and look for the FD on the tag. It's an automatic, AC car.
  The 79 TA parts car is a pitiful mutt that has seen who knows how many changes in it's former life. It has a Pontiac 455 in it from an unknown source. I will check that radiator also, out of curiosity, but I'm thinking my best bet is to get the original one in the 77 fixed.
  Thanks @firebirdparts for the great reply! 

[JDMopar]

 The radiator in the 77 I will be working on has a tag and the letters are FB. Definitely a B instead of a D. Looks like it's never been out of the car, has 4 rows of tubes thru the core, so maybe it's a HD cooling unit.
  The radiator in the parts car has no tag and only has 3 rows of tubes thru the core. Both cars are AC cars. I'll be getting the thicker core radiator from the 77 redone!

[firebirdparts]

I went through my build sheets looking for FB.  First one is a W72 automatic (they had a 3.23 rear gear).  HD cooling is not noted.  (would be VO2)





Not seeing a pattern really except that they're heavily optioned.

[firebirdparts]

Parts book says FB is a heavy duty radiator for 350, 400, 403.  It seems odd it wasn't on the build sheet, but I guess with enough options or some configurations you need the 4 core radiator, but they didn't have heavy duty cooling.  I did eventually find a 77 build sheet with heavy duty cooling VO2 listed among the RPO codes.  Maybe there was a different fan or fan clutch for that.

FA, FB, FC, and FU are all considered heavy duty rads in this parts book I have.  I have several published different dates, and that makes it interesting, as parts come and go.  The September 1976 version doesn't list FB at all.

[JDMopar]

 I have never looked for the build sheet, but hopefully it hasn't been turned into a mouse comforter over the years. The car is really well optioned. It pretty much has everything but cruise control. PS, PB, AC, PW, T tops. Black with all the gold stripes and accents. Some ding dong in the past spray bombed the interior to black, but it was originally tan. I think the interior code is SKN?
 I'm glad it has the big radiator, and I appreciate you digging into your stash to help.