727 With Gearvendors Unit in 65 Dodge Dart GT Convertible

[Austin Spencer]

Hey all, I'm currently working on rebuilding and putting a 727 with a Gearvendors Overdrive unit into my 65 Dart GT Convertible. I've got a 318, smallblock 727 that I'm rebuilding, and of course, the GV unit. Previous owner already had another 727 in there, so they had the work to make that fit in there, so this is more about the work to get the GV unit fitting within the transmission and driveshaft tunnel. I'll just be documenting this here for anyone in the future to get some ideas and see how I'm doing it. This is my first time doing any sort of sheet metal work on a car, so any tips or advice would be great too. I do work as a welder/fabricator so it's not too foreign.

Here's a few pictures of the section of the floor that I'll be cutting out. The unit sits right in between the front seats, slightly more toward the back. With the flange of the tailshaft and the unit, the larger diameter section is about 7", so I marked this cutout at about 9" long from front to back. I drilled out some holes every inch or so along that line, and used a dremel and sawzall to cut out that panel.

Here you can see the cutout, as well as the flange of the GV tailshaft. The main issue was the width, since the flange is too wide to fit in the tunnel. Height wise it would have been touching, so it needs to be expanded all directions, but width is the main concern. You can also see the beginnings of a slight problem I had, it seems my engine/transmission are clocked very slightly counter-clockwise, since my tailshaft is not fully parallel within the tunnel.

These are the dimensions and shape of the tunnel before I did any sort of bending and hammering to it. You can see it is a slight bell curve kinda shape, with those two ears at the top.

Using a hammer, some vise grips and a softer mallet I was able to turn it from the shape before into a semi-circle shape. I did enlarge it a bit further than this afterward, but this is generally what it turned out to be.

 

[Austin Spencer]

Here is the flange of the GV tailshaft within the modified tunnel now.

It's got quite a bit more room, and you can more clearly see the slight angle it has toward the passenger side. I then decided to put the whole unit in and see how it fit.

With the unit installed, you can see the angle very clearly. Looks like I'll have to work with my motor mounts in order to slightly rotate this whole assembly and get it parallel to the tunnel.

Here is a comparison of the section I cut out before enlarging it, compared to the section that was in the car that I enlarged. After this I did go and enlarge the whole section that I cut out, and it lines up pretty well. The GV unit being slightly angled to the passenger means that it touches, while the driver side has a good bit of space. I'd like to even it out so that it'll have at least 1/2" of space all around it, so working on getting the engine/trans/GV unit parallel to the center line of the car is the next big step.

Lastly, this is the speedometer output of the GV unit, and I know it comes with an extension. I may be able to get this to fit solely under the car, but it is angled slightly up into the floor pan. Not impossible, but it may require some clearance to avoid rubbing and a tight turn.

 

[Austin Spencer]

My current issue is just the angle of the transmission that I'm dealing with. I figure I can mess with the motor mounts slightly just to get it to line up better, since it can't be off that far since the unit fits, it's just a degree or two off. I'm not sure if there would be any other spots that could be causing this, so if anyone has any ideas that'd be great to know.

In the meantime there will be lots of prep and wire wheeling to do, as well as fixing a crack in the section I cut out that was there when I pulled up the carpet.