Honestly I'm not sure what those are.  My radiator is just bolted to the radiator support.  Maybe those are there to fill the gap on the side?  If so the radiator would almost certainly ave to install over top of them.  

They are filler or deflector plates to fill the gap when using a 20" radiator in the 24" opening.  The go on first and the radiator does not mount to them.  The picture you posted is mounted backwards I think.  If you upgrade to a 24" radiator the plates are not used.  The radiator sits in brackets mounted to the frame at the bottom and a bracket that mounts to the core support on top - it does not mount to the sides

=13pxhttps://www.summitracing.com/parts/sdk-c7zz-8a193-a?seid=srese1&ppckw=pmax-restoration&gclid=CjwKCAiAlfvIBhA6EiwAcErpyV9Pnzg3hFag15-YdY0jLqDlyGzHgb7HgWzPHwJeDWp-GD1OCJEpBRoCrQoQAvD_BwE

https://www.summitracing.com/parts/sdk-c7zz-8052-a?seid=srese1&ppckw=pmax-restoration&gclid=CjwKCAiAlfvIBhA6EiwAcErpyYpWxAxF-dgmTgkAKz-y7YPEsBcoEHbhCqiyql3ieFbtrPBkzdFzAhoC-f8QAvD_BwE
 

Here are pictures of mine.
Passenger Side:


Driver Side (behind generic "puke tank"):

I don't have any cooling issues, even with A/C and 100+ degree summers of South Mississippi.  I do have a shroud, so I'm sure that helps.  If I ever have to replace it I'll go to a 24", but in the meantime I don't see a need to replace it.

I'll have to measure mine, but it seems I also have a 20" radiator, because mine mounts like Michael H's, but I don't have those plates.  Probably just one more part the car was missing when I bought it and I never realized they were gone.  

MS wrote:

Jieve wrote:

Thanks Michael!
Does the installation of a 24" radiator require moving the battery on a '67? I thought I had read that some models require this.

No, they came from factory with 24”. Straight bolt in with use of new top and bottom retainer brackets.
24” aluminum radiator that has proper upper and lower formed tanks on ebay brand new $199. Brackets and rubber mounts cost you another $100

Adds 20% more cooling area

Well, that's good information to know... I took a screenshot of this to save for later.  I'm sure I'll eventually have to replace my radiator one day and this will be nice upgrade when I do.
I'm betting my shroud from my 20" won't bolt onto the 24" ?

Last edited by Michael H. (11/21/2025 8:22 AM)

I have a stock sized three row radiator in my 68. I have the spacer plates installed on each side to close the gap between the radiator and the radiator support. 

Jieve wrote:

Thank you all for the resposes. 
GPatrick, I read somewhere (I think on concours mustang forum) that '67 was a weird year where they had a one off side mount radiator setup for possibly not even the entire year. I don't have the brackets shown in the summit links and the original 20" radiator out of the car bolts through the exact same holes as those filler plates. Can't remember the orientation though. 

A 67 had more running changes than any other year ... 5 different hoods over the model year.
It also had a unique size big block radiator, 23", vs the 24" in 68
Bolted to the floor still has his original wrapped in cardboard!
 

Michael H. wrote:

I have no direct experience with this (obviously... you saw how mine is mounted in the pictures I shared earlier) but here is a picture I found online of a 24" radiator in a '67 Mustang.  It appears that the opening isn't really wide enough for it.

MichealH - thank you, I guess I'll pay more attention to this when viewing 67/68 Mustamgs. 
 

I have a feeling my '67 came factory with a 20". Not sure why a 24" would have those cover plates if they just end up blocking the airflow to the additional surface area, and I don't foresee the previous owner replacing a 24" with a 20" (although I guess anything is possible). 
Prior to posting this question I watched like 3 youtube videos about installing a new radiator in a '67, none of them had the cover plates that I could see. I figured on those vehicles they just got lost/removed at one point or another. 

Michael H. wrote:

BobE wrote:

I don’t have experience with the 67-68 Mustangs so help me out here.
Did the opening for the radiator on all 67 Mustangs come with the core support for the 24” wide radiator? 
If the 20” wide radiator was to be installed, the spacer plates would be installed on each side to cover the 2” gap that would exist in the opening.  Is this a correct statement?
My confusion; the pictures that MichaelH posted appears to be both the right and left sides of a 20” wide radiator installation.  So, wouldn’t that require the plates to be mounted facing inboard?  (I realize from the picture this wouldn’t work, and is the source of my confusion)
If not, what are the spacers for?

I have no direct experience with this (obviously... you saw how mine is mounted in the pictures I shared earlier) but here is a picture I found online of a 24" radiator in a '67 Mustang.  It appears that the opening isn't really wide enough for it.

That is not a factory 24” radiator. That is a larger radiator, a crossflow, that somebody cobbled together. The factory 24” fits like it is made to go there. N fact, the car was designed for the 24”, then the 20” was adapted to the car, hence those two filler panels to block the air from going around the sides

Thank you for posting that.  That is a much nicer fit.