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1963 floor pans, automatic vs. standard shift?

Pete Phillips

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I have run into a major problem in the restoration of my 1963 Wildcat convertible. It's a factory four-on-the-floor car, but the original floor pan was so rusted that I had to replace most of it with another floor pan out of a 1963 Wildcat 2-dr. hardtop automatic transmission parts car. I had an area welding shop do the work a few years ago, and I thought they did a good job. Now that I have reinstalled the engine and 4-speed transmission and drive shaft back into the car, I am having impossible clearance problems with the transmission and drive shaft tunnel. I am using the original drive shaft, the original 4-speed transmission, a replacement carrier bearing that was installed and working fine in the car about a month before I took it apart for this restoration, the original engine mounts, the original 425 engine. The transmission and front U-joint simply will not fit in the transmission tunnel. It's not just a few hundredths of an inch, it is more like an inch too low. I have tried everything I know, and finally had to cut the top off of the new transmission tunnel just to get the transmission and cross-member to bolt into place on the frame. Now, the transmission and cross member are bolted back into place, the top is cut off of the tunnel above the transmission, and I am going to have to get someone to fabricate a new transmission tunnel, or add an inch to the existing one. And I still have the front U-joint which is hitting the transmission tunnel where I have not cut it out yet. I wondered if the new floor was installed too low, but it is pretty obvious, when you cut out the old floor, where the cut is and where the new one goes. So, does anyone know if Buick used transmission tunnels/floor pans of different heights for the standard shift cars? I can't imagine them doing this, as so few manual shift cars were even built in 1963. Pete Phillips, BCA #7338, 1963 Wildcat Conv. (Can't seem to get this thread to start a new paragraph or new line)

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It seems like a strange situation all right...

Based on the data you gave... I think that a good fab shop should be able

to bend up a new tunnel, then cut and fit it so it clears the chassis (and

rear seat without issue; and should not take more than a day or so.

On the other hand, adding a metal section joint might be a slightly faster route

by using the top you cut off; riveting in the sectioned piece in (top and bottom) till it fits

right; then weld it up. Either way, since the tunnel is a major structural element to the

body it'll be important to use a continuous weld ... not just rosettes or tacks.

It does make you wonder if the shop just installed the auto trans pan too low or if stick shift cars were so rare that

they just modified as needed on the assembly line....

got any pics?


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Is it the photo, my eyes, or, is that crossmember looking

bent in the upward position by about an inch or so....?

From the photo it almost looks like the thing was rolled over a boulder.....

Doesn't look symmetric to me either ... kinda bent to one side

If it's not bent, Could it be upside down?? Thereby, dropping the trans

down at least an inch?


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If it makes a difference, the trans lever cutout on my automatic floor shift Cat was done with a torch. I assume it was done so at the factory, thus seeming to make your theory of a single floor pan (regardless of trans choice) a strong plausibility.

Are your body mounts in place? That is about the only thing I can think of assuming the floor was welded in the correct place. I think that the next step would be to cut out as much pan as necessary and then fabricate a floor making sure your console will fit. After the trans shift lever and console are happy, finish the floor so that your carpet won't be all bunched up and funky. Also, keep in mind that you shouldn't waste your time ordering a carpet after all of this work is done. You are going to have to have one sewn by an upholsterer, cuz an "off the shelf" version won't fit.

Isn't Gas Monkey close?


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Wow, what a conundrum. There has to be two people in the Buick Club with '63 Wildcats that can compare tunnels side by side. Am I mistaken in thinking that a lot of manual trans cars in the 60s had a kind of "add-on" tunnel for the shift linkages and what not? Is this something that might be in a 1963 Body manual???

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Body mounts are in place, in fact I put new body mounts on it a couple of years ago when body was off the frame, so if anything those would be higher and less compressed than the old ones. I think the sharp eyes that see the slight curve in the center of the cross member might be onto something. Manual shift cars in the 1960s have an extra brace that attaches to the top of the transmission tunnel, to help locate the shifter plate, but that won't affect transmission tunnel height. This is a four-speed car with shifter plate and no console. I do appreciate all of the ideas and suggestions. Pete Phillips

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Pete, this are random thoughts but they might be worth looking into. Is the transmission mount (rubber) correct? If it's too tall, it would push everything up. Have you checked the pinion angle against the angle at the back of the trans? The nailheads (mostly in Rivieras) I've seen have a tendency to sit lower in the back than yours seems to. If the body and frame and tires are all correct, does the carb face on the intake engine sit level? Use a level and check this out. In order for the carb to sit level, the engine has to slope to the rear. I too think the trans cross member seems to have a bump in it. I would have a tendency to work on the trans cross member rather than playing with sheet metal. MHO.


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Guest wildcat465

Hmmm. Wasn't there some posts regarding a trans mount on a stick shift car a while back???

We assume the transmission fit before??

What changed?

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Considering how DIFFERENT the shapes of the automatic trans and the manual trans might be, including the 4-speed shifter mechanism, it would make perfect sense for the 4-speed manual trans floor front section to be different . . . OR an "off-line" modification was done to the automatic trans ("normal") floor pan section "in plant". I suspect the column-shift 3-speed manual trans (with lower installation rates than the automatic) would use the same front floor section, BUT the 4-speed manual trans would require something different (typically being a physically longer transmission).

Considering the fact that Fisher Body was usually trying to decrease production complexity (with many "unseen" body parts being more common between the various GM carlines, as I understand), it could well be that the front floor section (with the trans hump) for a '63-4 Biscayne/BelAir/Impala or Catalina/Bonneville, which also had 4-speed manual transmission options AND higher installation rates of the 4-speed manual trans, compared to Buicks, might be the front section to gauge things with rather than a DynaFlow Buick's front floorpan section. Might even find one for a Chevy or Pontiac in the repro floorpan sheet metal suppliers! IF such a part is available, I suspect it would be an easier "fit" than a "full fabrication" situation.

I ran into a similar situation in adding factory dual exhaust to my '80 Newport. I'd always wondered why the similar '79 Cordoba "300" was not available with a power driver's seat. I found out when I discovered the front floor pan section for such a factory dual exhaust car (with DUAL factory catalytic converters, one on each side for true duals) also meant the floor pan had to be clearanced for the lh cat and heat shielding . . . which required an adapter to mover the seat tracks on the lh side closer together, such that a power mechanism would not fit between the resulting 3" wide space. When I saw some '79 Chrysler police cars in the salvage yard, I also discovered that hidden under that 3" of padding was a plate for a console shifter to mount to, as the '75-'79 Cordobas typically had, as well as the similar other Plymouth and Dodges of that time. With the Chrysler, I was able to adjust things down a little and get sufficient clearance without any "hammer action" . . . and it's still that way, sans heat shielding (which I also have, including bolts). When I later encountered a Dodge St. Regis police vehicle, I looked under the lh seat and found the "adapter" to allow the existing-width seat frame and seat tracks to be used on the floor pan for the dual exhaust car. I'd suspect the availability of a lh power seat not being available on a "police vehicle" to be more of an issue with "bid prices" than otherwise, until I figured out what was really going on under there.

Just some thoughts,


As for "Gas Monkey" . . . keep those guys inside of Dallas County! Haven't seen the "Dallas Car Sharks" on Velocity Channel, though. To me, they run a "close second" to Chip and the "Overhaulin'" guys, but at least Gas Monkey is doing it on a budget of sorts, without BIG sponsors and such, which can tend to affect how they do some things . . . AND they've at least found some interesting cars to deal with, which might be a plus.

Edited by NTX5467 (see edit history)
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