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1/01/2015 11:36 PM  #1

Supplemental 24" Radiator Installation Hints

I decided to install a 24" radiator in my 66 convertible project.  After some research I ended up with a DeWitt's 379 style radiator - big block 67 to 69 and/or 70 small block with A/C which has a passenger-side upper/inlet and driver- side lower/outlet.  Very pleased with the radiator construction and the price was about $100 less than an equivalent Griffin.  It is a two-row aluminum unit and the upper tank is dimensionally similar to the original four-row radiators.  I started the installation with the upper bracket and quickly figured out that hood clearance might be an issue.  After a few emails with MustangSteve I learned two things - a paint stick is required for fitment and it ain't rocket science (in other words I was over-thinking it).

First - the paint stick - place a paint stick across the frame/body area in front and drop the radiator in place.

The lower brackets extend across the strut rod support brackets and the radiator support in this area.

After checking the fit and spacing, my radiator fit a little better with two paint sticks and the position of the radiator filler neck and cap would still clear the hood.  I made basic brackets cutting some scrap 1-1/2 square tubing and used a portion of the lower radiator support brackets I purchased - save your money and make your own.  The brackets are about 3-1/2" long and are 1/2" thick/deep at the back end and 3/8" at the front end to account for the radiator support sheet metal.  Here are two views of the simple brackets.

The filler on the raditor is not centered.  However, when installed the filler neck is centered in the car.  This offsets the radiator towards the left/driver's-side of the car by about 1" and provides more room for the battery.  To fit the lower support area of the radiator the brackets were also offset towards the left.  The next pictures show the radiator tank with the offset filler (this is offset is the same as the original radiators) and the lower radiator support area of the DeWitt's.  The DeWitt's differs from some of the other radiators in that the lower mount area is not part of the lower tank but instead they are fabricated from square tubing.

This view shows the driver's-side bracket in position on the frame.

The brackets were tacked into position, the rubber pads were inserted and the radiator was dropped into position.  After my initial mistake of installing the upper bracket at the top of the radiator support I was left with the alternative of filling the holes or slotting them.  For now, flat washers hide the slots and I doubt anyone will pull the bolts at a car show to see if there are slots.  I added a flange to the hood latch mounting frame but if the radiator bracket holes are low enough, this is not required.

If I was starting all over knowing what I know now, I would have dropped the radiator onto the lower brackets and measure where the upper bracket sits below the top of the radiator support.  Pull the radiator and place the bracket back in position and mark and drill the holes through the radiator support and the hood latch.  This picture shows where the bracket sits in my installation.  All cars vary and the radiators may vary from one supplier to the next so mock up and measure for a custom fit.

The next pictures show the final fit on top and sides.  The radiator support opening was modified according to MustangSteve's big radiator installation instructions which opens the area to match the radiator.  I have some rubber trim that I will install around the sharp edges after paint.  The overflow hose is going to be a little tight so I may notch the top of the radiator support slightly to clear.  After fitting a big block fan shroud, the next step is to fab up the revised battery tray.  I tried to install a late model reverse rotation clutch and fan from a '91 but there is not enough room so I am installing an 18" reverse rotation flex fan.  With the radiator in position I have about 1" clearance which should be close to ideal with the shroud.  Thanks for the support Steve!



1/02/2015 10:09 AM  #2

Re: Supplemental 24" Radiator Installation Hints

Thanks - great write-up.  I was contrasting how you did it w/ how MS does it in his FAQ and had a few questions, if you don't mind:

Is your radiator dimensionally different than the stock one MS uses?
Are you going to have to have custom hoses made like MS did, or is it possible some stock hose from some application will fit?
Are you going to use a shroud and does a stock one fit?
Lastly, do you have any idea when a radiator like this is necessary over a stock 65/66 sized (or one that the same width but thicker) aluminum high efficiency radiator? 

Cheap, Fast, Good:  Pick Any Two

1/02/2015 12:05 PM  #3

Re: Supplemental 24" Radiator Installation Hints

The DeWitts is dimensionally the same as stock and is the same as the 24 inch install on the MS main page.  It is probably overkill but I needed a new radiator so I went big.  I would probably go at least with the 20 inch over stock.  You can't make a small radiator bigger and since engine heat is controlled by the thermostat, I do not think a large radiator hurts.  My engine is a supposed 350 hp roller block crate motor and it won't be a problem to cool with this setup.  Waiting to install a shroud but the stock big block should fit well.  I think in the write up the custom hoses were for A/C.  I am going to try a stock 1970 small block with A/C hose for the lower and a stock 1991 5.0 fo the upper due to the serpentine setup.  I have a passenger side mid mount compressor so I will need custom A/C hoses for sure.  I have read good things about SOME of the aluminum stock size replacements but do google searches for reviews.  Aluminum by itself is not better if it is pooly constructed.  Stay away from epoxy construction if possible because it may limit heat transfer and they cannot be repaired.

     Thread Starter

1/02/2015 11:39 PM  #4

Re: Supplemental 24" Radiator Installation Hints

Stock hoses work.  This same size radiator was available with all V8's that were available in 67-70, so there are stock hoses that fit no matter what engine you use.  The serpentine belt system may require a later model Fox body hose.

Normally all four of those bolts on the top bracket are straight in line with each other, and there is no need to slot the holes.  If you look at the top clamp bracket from the side, it has a pre-stressed condition built into it, )mounting flange is at less than 90 degrees) so when you tighten the bolts it pulls it down tighter against the top of the radiator.
Maybe your radiator is a little higher up than mine due to differences in the lower mounts.

I do not think there were ever any factory 4 row core radiators.  Most were two row and the big blocks got three rows.  Even BOSS 302 was not four row.

Money you enjoy wasting is NOT wasted money... unless your wife finds out.

1/04/2015 8:23 PM  #5

Re: Supplemental 24" Radiator Installation Hints

All the parts houses offer the upper rubber pads in a four row width.  I got the three row pads and they were not wide enough but trimmed nicely to fit.  Several parts houses also offer four row raditors but I now assume that these are aftermarket.  The picture you sent me showed the bolts all aligned but I needed a little more height in mine.  I had to slot them because originally I thought the upper bracket mounted all the way up at the top - my error.  I just need a second car so I can do it all right the next time!

Last edited by GPatrick (1/04/2015 8:24 PM)

     Thread Starter

8/08/2017 7:37 PM  #6

Re: Supplemental 24" Radiator Installation Hints



Board footera

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