I have had my 67 Firebird 400 4 speed for over 20 years. I ran in the 180-190 range, until I took of the after market flex fan and installed the original fan (I like everything original). Now it's running 190-230 and sometimes 240. I installed the original 1 1/2 then the 2/12 spacer, but its not helping. What is the original spacer length and what suggestions do you have? Right now, I have the 2 1/2 spacer and it sits about 3 inches from the radiator. Thanks in advance for your feedback...

What is your stock fan, clutch? I believe you need a clutch or flex fan for 67 400.
Definitely not a 4 blade.

Look at thread: #281957

7 blade clutch fan, + fan shroud with whatever spacer allows the fan to be 1/2 way into the shroud. Do you have the factory 400 radiator block off plates installed?

235-240 is overheating and you're risking damage. If it was ok before I'd go back with what worked. I have a clutch fan if you want to give it a try. It would be stock for an A/C car.

Wow guys! I think I have the 5 blade and not sure which clutch fan I have, but I'll check and get back to you. All I want is the original set up, so the original fan and clutch would be preferred. Original spacer size? Does anyone know original fan, clutch, and spacer info? Part numbers? I'll also see how far the fan goes into the shroud. Thanks!

How do I find that thread number?

I'll take a picture of my 67 for you tonight. I can't remember if it is 5 or 7 blade fan. Definitely clutch style though.

Thanks dam1960! Thanks HaroldB for the thread...

Ok I did some research and I have narrowed it down to these part numbers:

FAN:
9798940 or 542621 4 blade 19 inch exc ac HD, or A.I.R. (which I have)!
480033 or 9779005 all 8 cyl with HD (what does HD stand for) exc ac 5 blade 19 inch
N.L.A. or 3999012 7 blade 19 1.2 inch

FAN CLUTCH:
477957 or 9786404 All 8 cyl exc ac

FAN SPACER (I have both):
3927794 All 8 cyl exc ac 1 1/2 inch long
535253 All 8 cyl exc ac 2 1 /2 inch long

I have a 67 Firebird 400 no ac, but a CA model with A.I.R.

With this info, what fan, clutch, and spacer should I be using?

Here we go. To the best of my knowledge the fan, spacer and shroud are original. I replaced the clutch a couple years ago.

The fan is 7 blade 19.5". The spacer is 1.5". The fan blade tips are approximately an inch inside the shroud.

My car is a 400 auto, non AC and non AIR

This is VERY helpful thanks! My fan sits closer to the radiator and isn't as exposed as yours. Your firebird fan bolts directly to the pulley and mine has an additional 1 1/2 inch spacer, so I'm going to order a new fan clutch and remove the spacer and see how it goes. I verified my fan is from a 69 Firebird (3991431) but it's also a 7 blade 19.5" so although it might not be original for a 67, it does have the right amount of blades and length, so I'm ok with that.

I appreciate all your help, the pictures made all the difference!!!

No problem. Glad to help. Good luck