Dino Diaries - Feb 28, 2025: What's Good for the Convertible is Good for the Coupe!

[Jason Edge]

I have made some "factory" upgrades to my 64 Coupe de Ville by installing some options available to my Coupe de Ville such as power vent windows, tilt steering column, am/fm, 3 way rearview mirror, right side mirror, limit slip "controlled" differential, Eldorado horn, HD coil springs, vinyl top, etc., but have also opted for a couple of upgrades by swapping in parts available only on other body styles.

All three 1964 Cadillac convertibles I have parted over the years, had a plate welded on the bottom of the front transmission crossmember. I assume it stiffens up the car by preventing twisting of the frame which I guess might be more prominent on the convertibles.  So... I had saved one for "Dino" and installed as you see below.

The crazy thing, as I do not recall a different part # in the master parts book... but worth me taking a look. If you have a 64 convertible, or really any 64 body style with the Turbo HydraMatic transmission I would be curious if you have this plate on the body of your front trans mount?

[Dwight Hargrove]

Hi Jason, looks great!  By the way, where did you get that exhaust crossover pipe.  It looks like a very good quality piece.

Dwight

[Jason Edge]

 The exhaust was the stainless set from Classic Exhaust out of Ohio and was installed in 2012. It is quality parts and was reasonably pleased it was not an exhaust fit as it went under the rear section of the car and required some cutting and bending but not too bad. I was also in a big hurry with grand schemes to take it to the GN in San Antonio (and have yet to take to a GN!), and instead of trying to use all the correct brackets at the frame, the exhaust shop welded their stuff in place to hold. It probably is more secure but look under it and while it is routed correctly the brackets are not factory. That is one of the many things to address on the car at some point. 

[Logan Robb]

I can confirm that my 64 Fleetwood did NOT have this welded on plate. I was just under it to replace the transmission. 

I agree with your reasoning that it was meant to stiffen the car up but only because I can think of no other reason to have done this! I do find it hard to believe that that little addition would add that much more rigidity, then again, I am not an engineer!

[Jason Edge]

 I will say it is a very thick plate but you wonder h ow much it ads at this point. I can say that all convertibles I parted, which has only been a sample of 3, had the plate.
There are several things to consider, especially given the fact it is not listed as a separately in the 1965 Master Parts Book (by far the most accurate of what actually came on the car since it is the nearest edition to the mode year). 

- A few scenarios:
1) used throughout the entire 1964 production model year, then simply not carried, listed as a replacement for the convertibles if needing one in 1965 or later. 

2) used first part of the 1964 production model year then discontinued and regular one used instead.

3) used intermittently in 1964 production model year (like the 7 bladed clutch fan for 1964 AC cars), where it was started at some point then stopped. 

4) more of a supply and demand thing like the contoured vacuum can vs the coffee can type vacuum can on 64's with AC.

5) a mistake in the Master Parts Book by omitting it! I have a few mistakes but not m any.

6) I need to do a another deep dive into the master parts book but 95% sure there was  not a separate one listed.

With that said, it would be interesting to hear from some convertible owners to fin out if they have that plate welded to bottom of front transmission crossmember or not!?

[Phillip Hill]

As a 63 convertible owner there is a plate on the crossmember I first thought it was some sort of aftermarket addition but after some research I found out that it was standard.when I removed the crossmember it was full of krud .it took some cleaning ( I think it had half of the USA in side it)once it was clean it was kill rusted and reinstalled.

[Jason Edge]

Phillip, Thanks for the feedback. This is the 2nd part of the question - do 1963 convertible's with the HydraMatic transmission use a reinforced front crossmember.  I actually parted a 63 convertible 20+ years but did not think I had any pictures of the cross member but found the crossmember in the corner of one of my pictures. I cropped in and took out the shadow and there looks to be a plate there. See picture below: