I think my 64 has a 65 engine and trans combo in it? Help!

Hello everybody, well this has been an interesting journy. I am still trying to figure out why I am getting a vibration at the flywheel area, I suspected something was replaced so this lead me to look at the transmission ID # on the side of the trans, including the engine itself. I can't believe it took me this long to figure it out, but the ID # on the trans is AA-65, and the 429 engine has to be out of a 65 as the water pump lower hose outlet connector goes to the passenger side of the radiator not the drivers side like the 64 429 is setup!!

What really got me thinking, is I looked at the motor mounts, and the oil pan sump, not only do the mounts look newish, but the oil pan sump is front facing. This is why the oil pan was cut and rewelded in order to fit in the 64 X-frame.

Also if Jason is reading this, I can't use those flywheel covers I got from you as they don't fit the 65 THM trans. The mounting holes are different.

I have a theory, my 64 was made in July of 1964, so it's a very late in the year model build. Could the factory installed a 65 engine and tranny since the plant was getting ready to build 65 Caddys? Or do you guys think someone replaced the entire unit as the previous owner might of blew up the old one? 

Or it could be that the transmission was replaced with a 65 THM mated to the 64 429 engine bell housing and this is what is causing transmission vibration?

I tried looking for the engine serial number by the lower side of the block and I couldn't find it.

I'll try again later on today, but if anyone can help lead me to an answer that will be freakin fantastic!!!!!

Gracias Mi Amigos.

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Comment by Clovis on November 10, 2016 at 9:34am
Amen there Tony! Just the fact alone that there is a website dedicated to these two specific years is incredible. Most sites try to cover a large segment of years and you have to sort through many posts of the same subject to find your years issue. Not here, plus we have Jason, Russ and yourself to boot. This is really one of the better sites for car enthusiasts because its active and specific to our cars.
Comment by Tony and Ginny 429 on November 9, 2016 at 11:54am
In my opinion will always have the facts and final word ( and PICTURES to boot ) on any subject posted here as he is our true authority on the subject of our cars
Having knowledge of all models available in 63-64 which is very different than knowing the one model you may own of our year Cadillacs
It is Truly a blessing we have him ( webmaster ) and this site to consult when we need help on a given subject
Thanks - big guy !!

Comment by Clovis on November 9, 2016 at 10:02am
My engine is a 65 but all parts attached to it are 64 including the transmission. The only notable difference is the motor mounts and they don't seem to be poorly built. My vibration is not really noticeable to anyone but me, so it's very slight. But it's enough to warrant looking for it because I'm ADD. LOL
Comment by Tony and Ginny 429 on November 8, 2016 at 4:55pm
Do not drop a screw into the carb
Comment by Tony and Ginny 429 on November 8, 2016 at 4:53pm
You are running a bit lean if the plugs are gayish
Glad all the plugs look good and the same
The plugs should be burning a brown paper bag color
Do concider going one set richer in your primary jetting
If you have a Carter or Edelbrock carb you can do that by changing the primary jet metering rods
They are located under a little flap with a screw at the top of those carbs
Bring the metering rod you now have to the auto parts store and they can give you one size richer metering rod to install
That easy
The rods are a bit spring loaded so watch for that removing it

Comment by Chris on November 8, 2016 at 4:15pm

Tony, the engine and trans runs strong and the car gets up fast. Still a lil shaky at idle sometimes, but much better than from a year ago. I actually checked the condition of the spark plugs to see how the engine is running, and they are perfectly grayish color, no carbon deposits, oil or gas on the plugs, so I know that the engine is in perfect tune shape.

I believe the 65 trans with the added switch pitch, increases the torque output tremendously as the car takes off like a rocket. I am still having the vibration problem, and plan on taking it to a reputable trans shop here fairly soon. My issue I don't believe is a motor mount problem, but the torque converter. It could possibly be misaligned.

I notice the vibration decreases for a split second or so when it shifts from 2nd to 3rd gear, and the vibration gets severely worse the faster I go. Could the band's be worn out or needs an adjustment? I was wondering about this the other day, maybe the bands need to be looked at.

The shift points are flawless almost undetectable at times, there's no hesitation or roughness, or slipping or any noises of that nature, so those are good signs lol.

Comment by Tony and Ginny 429 on November 8, 2016 at 3:48pm
How does your 64 with the 65 engine ( and 65 trans ? ) perform for you
Are you driving the car enough to know or is it in a state of repair ?
Comment by Tony and Ginny 429 on November 8, 2016 at 3:42pm
Looks like you may have found your vibration problem
Possible missalinement due to fabricated ( possibly home made ) motor mounts
with a 65 engine swap
That is if you feel you need to correct the motor mounts you are looking at
Wondering if a Hot Rod fabrication shop or a good body shop could be helpful in correcting the motor mount issue making for a better solution if you need that
MM fabrication would be a basic
Hot Rod shops are always installing different engines into different bodies as it is what they do

Be sure your engine ( and trans ) is sitting in the correct position of the stock 64 engine and trans i would think to be sure the MM are serving there intended purpose

Chris may have an issue if his engine sits low and back , closer to the fire wall that he may have to look into
Chris did not say he was having any issues with the way his car rides ,just that he sees it is a 65 engine in a somewhat different location under the hood of his 64
Comment by Chris on November 8, 2016 at 5:42am

That's crazy Clovis, so I am not the only one that has this problem. It's always good to catch these things especially when looking up engine parts for our cars like water and fuel pumps. The 65 engine and trans were a little better than the 64's, so I'm not complaining. Lol

Whats weird however is that the person whoever installed the 65 engine in my 64 somehow was able to still use the same oil filter housing, It's like they totally frankensteined it.

The only explanation I can think of why they dropped in a 65 motor and trans was because probably the original engine blew up a very long time ago and maybe the owner decided to drop in a 65 engine from another Cad from a junkyard for really cheap, but then realized he couldn't match the 65 engine to the 64 turbo 400 trans, so he or she had to hunt down a 65 trans in order to make it work.

Comment by Clovis on November 6, 2016 at 12:54pm
Looking at the pictures on this thread it appears that I have a 65 block with 64 parts installed. My frame mounting holes were not moved though just the mount itself was refabricated to fit the motor.


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