Also may have missed somewhere in this post but is this an about or a 4 speed?

Correct, 400's and A/C cars had 4 rows...I think. Have to check my 67 to be sure. Its original.

How sure are you about that? Both of my 400's (w/ A/T) appear to have the original rads and they are both three core. Have never had an overheating issue.

My 69 400 A/T with A/C did come with a 4 row from the factory!


Stealth, what temp stat are you running? Also, isnt 36 degrees a lot to be running at idle?

The 4 row may have been an A/C or 4-speed thing.

Although my 350 4 speed also has a three core.

A/C would have been a great reason.

Does anyone have any literature or factory build info regarding the 3 or 4 row?

The a/c 400 cars had a 4-row, but I believe all the others were 3-row. I'd have to check on that though to be sure.

Yes, I basically run a locked out distributor at 35-36 degrees timing, but instead using a timing computer to retard the timing to start the car, it's all in my vac advance. Initial is still low, and the car starts fine, then the vacuum advance quickly pulls, and the car idles relatively smoothly. With the weights/springs I use, I get around 50 degrees while cruising, and 32 total under WOT.

I have a pretty radical cam, and wanted to disguise some of the lumpy/choppiness, so it sounds like a RAIV cam with 1.5 rockers.

1967 specs. Coolant capacity.
6 cyl 12.1 with A/C 12.7
326 18.6 with A/C 20.2
400 17.8 with A/C 19.4

For 68, everything same except 350 has same coolant capacity as 326.

I don't see a dilineation on auto vs 4 speed yet.

aahh, makes sense now!

Didn't get home till late from 2nd job.
Think also have one out of a 68 400 a/t car. Don't know if had a/c. Get the letter codes and ck tubes 2nite.

Yes, my 69 A/C car (350 orginally) came with a 3 core.

I recall quite a while ago (just remembered this now...guess old age catching up with me) that Pontiac didn't actually use 4-core radiators on Firebirds. I just checked the assembly manual, and that seems to be correct. The 3-core was the largest.

The 3-core was used on 350 cars with HD cooling specified, and all a/c cars. Same radiator was used on 400 HO and Ram Air cars, and 400 cars with HD cooling. There was a 'Super Cooling Radiator' option, used on full sized Pontiacs only.

I seem to recall a discussion on another forum about a 1969 Trans Am RAIV 4-speed, and there was doubt it came with a 3-core radiator, but apparently it did. Ditto for another example where a fully loaded Firebird 400 w/ac had a 3-core HD radiator.

My .02 cents

That seems to gel with what my 400 cars have.

it could be a 3 row , its an aftermarket aluminum rad from summit racing. its an automatic TH200-4r 2000 RPM Stall out to a 3:55 posi.

My 67's letter code is UQ. Is original to car and has 4 rows.
The 68 looks to new. Must be a recore. Letter code tag is missing, but its also 4 row.

Have you recently re-built the motor? From my radiator shop days I seem to remember a few cars that came in running hot after fresh re-builds that had plugged radiators b/c they did not add a rust inhibitor or they had a lot of scraps blocking the tube entrances.

Does the car run hot at speed? That is not a fan issue. Does it steadily increase in temp or jump suddenly?

I had the overheating problem as well still after putting in new bigger radiator. Ended up putting in a bigger thermostate and solved the problem