700R4 Swap into '66-'70 small block B-body

[Powerflite]

I am finishing up a 700R4 conversion to my '70 Satellite 318-904 wagon and thought I would let people know what is involved with it. I figure my wagon is worth about $5k even after an overdrive conversion so it didn't make much sense to spend $4k for a 4L60E kit from Keisler. But this car is my wife's daily driver and the overdrive would be a much better option to running 2.76:1 gears in a heavy wagon. What to do? Enter the 700R4.

I originally wanted an ultrabell conversion for the 700R4 which would be as compact as possible to give more room compared to using an adapter. No such luck. As far as I could tell, an ultrabell conversion doesn't exist for Mopar-700R4. :icon_sad: So I purchased an adapter that uses a 1/4" plate with 3/8" spacers on the torque converter and a spacer on the starter as well. It also came with the custom flywheel & hub necessary for the conversion.

 

[Powerflite]

I was able to ream out the transmission mounting hole for the lowest bolt on the right side next to the oil filter to allow one 7/16" bolt that goes through both the trans and motor to hopefully give the adapter a little more strength.

 

[Powerflite]

The 700R4 gets big where the tailshaft mounts to the end of the transmission. Beyond this point, the transmission won't fit through the stock T-bar mount in the tunnel. With the added length of the 1/4" adapter plate, it became necessary to move the motor/transmission assembly forward 3/8" (an extra 1/8" for more clearance) to keep the tailshaft mount ahead of the T-bar mount.

 

[Powerflite]

Even after moving the engine and trans forward 3/8", the upper tailshaft mounting bolts interfered with the T-bar tunnel. So the 2 upper bolt holes were countersunk and fitted with flathead screws.

Everything so far was going very well until I realized that the speedometer cable exited right into the T-bar tunnel. :angryfire: I came up with 3 possible solutions to this.
1. Drill a hole in the crossmember and route the cable through it.
2. Weld tabs on the tailshaft housing to rotate it 30 degrees downward. This would allow the cable to go in between the tunnel and crossmember.
3. Run an electronic speedo.

I chose to run the cable through the T-bar tunnel since that seemed to be the easiest.

The 700R4 mount is exactly 1" lower than the mount on the 904. So to make a good mount for it, I just welded 1" strips to the top of the original Plymouth trans mount and drilled holes 1" above the originals.

 

[Powerflite]

The GM trans mount is also wider than the 904 mount. So I then welded tabs to the side of a Plymouth poly-urethane mount and drilled holes into it in the proper location. The poly-urethane can take more heat from welding than the rubber can so that is why I chose to use an aftermarket mount.

Also, I was able to use the STOCK driveline from the 904! That came as a welcome surprise. I just purchased an extra length transmission yoke for the 700R4 from Fastshafts and used a 7260-1310 conversion u-joint to mount it. If you get a yoke that is too long, you can cut the end of it to the exact length that you need. That is what I did.

You can also see in this picture how close the upper portion of the tailshaft mount gets to the T-bar tunnel.

There is a round governor on the right front of the transmission that required a small dent in the floorpan to clear it, but it really didn't need much of a dent to make it work well.

 

[Powerflite]

The cable exits through the bottom of the T-bar tunnel in a location that already had a smaller hole from the factory. Routing the cable required a 3/4" hole in both locations.

I also chose to automatically engage the lockup on the 700R4 at 42mph with a speed sensor from B&M that attaches to the speedometer cable. You can see it in this picture. It includes a control box up top that allows you to overide it and adjust the lockup speed. My only complaint with it is they didn't provide a good way to mount the thing. I will probably put some good quality foam between it and the T-bar and strap it to it.

The cable routing looks worse that it actually is. There are some bends in the cable but they are not too sharp to cause a problem. I still haven't figured out what to do about the backup lights and neutral safety switch. As far as I know, GM put them in the shifter, but I may just bypass the neutral safety switch and live without the backup lights for the time being.

 

[Powerflite]

Right now I am still working on the shifter conversion, cooling lines and TV cable attachment. This is a picture of what I have come up with to connect the column shifter mechanism, but I am still working on it and it needs some changes. I will update this when I get it done. The cooling lines route on the right side of the car now and I am trying to figure out how best to route them without picking up too much heat from being close to the header.

 

[Powerflite]

My total cost is:

Free trans taking up space in my garage. New rebuilds run $500-$600 typical for < 400 horsepower applications.
$460 - adapter
$150 - speed sensor
$30 - longer speedometer cable extension
$50 - Fastshaft yoke
$20 - conversion u-joint
$10 - straight cooling lines
$40 - poly trans mount

Total: $760 + trans & converter. Much better than +$4k (probably more with the driveline stuff) necessary for the Keisler kit. If you don't mind manually locking up the converter, you could even shave $200 off this amount.

Unfortunately, this conversion won't fit into an A-body. It is too long. I am not sure if it would work out as well with a big block ethier, but it might be worth looking into. E-bodies and late B-bodies would likely be able to do it easier since I think they have a little more room to the T-bar tunnel than the earlier B-bodies do.

 

[rolling_Thunder]

Not to be a smart *** - but I am just curious why you didn't go with a A500 or A518 ?

 

[Powerflite]

As you can see, I did this conversion without cutting my T-bar mount except for a 3/4" hole for the speedo. Going with an A500 or A518 would require extensive cutting and modification that I didn't want to do. As it is, I could go back to stock without too much trouble if I choose to do so.

 

[rolling_Thunder]

makes sense. I am looking for an OD trans for my 68 Satellite -

 

[blackblazer717]

Awesome writup, this should be a sticky

 

[STREETREBEL]

I have a 700r4 I would love to put behind my 440.
It's built with the heavy case and has a 3000 stall.
And I have a B-body!

 

[Greg Ducato]

Nice write up, the 700 makes a great swap candidate for the B-body. Wilcap sells an excellent adapter kit for the A or B engines made of billet aluminum, a little more expensive but really nice quality and it comes contoured to the block.

 

[Powerflite]

Yes, but the Wilcap adapter is too thick. I can't remember, but I think it is around 5/8 to 3/4" thick. That would push your motor even further forward. Not good. If you moved your motor forward that far, you would likely have trouble with the carb linkage, header clearance etc. But the 3/8" shift that I used didn't cause any trouble, at least with the cheap headers I am using.

I used the adapter from TCI because it is only 1/4" thick to minimize the total length. But what a pain in the neck that was to cut out the shape I needed from the large square plate they gave me. The benefit of doing all that cutting was that I could make it like I wanted it. That allowed me to attach the stock starter support bar below the starter to give it more support during cranking.

 

[Powerflite]

Some good news is that there are 1/4" adapters from TCI for the big block too. So potentially, you could use the same conversion method on your big block cars. Although, you would need to spend more money on making the trans live under big block power.

 

[Cranky]

As you can see, I did this conversion without cutting my T-bar mount except for a 3/4" hole for the speedo. Going with an A500 or A518 would require extensive cutting and modification that I didn't want to do. As it is, I could go back to stock without too much trouble if I choose to do so.

How extensive is the modifications for the A500 trans? I've seen the swaps done with them before and it didn't seem to be as much work as what you did....just saying. Nice write up none the less.

 

[wedgie]

Out-freakin'-standing! Powerflite is a true "hotrodder" by making use of what he has and thinking outside the box. Thanks brother.

 

[Powerflite]

How extensive is the modifications for the A500 trans? I've seen the swaps done with them before and it didn't seem to be as much work as what you did....just saying. Nice write up none the less.

Last month at Spring Fling in Van Nuys, CA, I saw an A518 swap done in an E-body that was pretty slick with no mods to the T-bar mount. They just machined the structural fins of the trans tailshaft to get it to slide up snug into the tunnel. When I saw that, I stopped my GM conversion and went to work to try it out on my Satellite. I pulled the A518 out of my garage I have saved for my '56 Savoy and numerous measurements later, I realized that the T-bar mount must be further back on the E-body by around 1.5" in order to make what I saw work out. The end result was that I couldn't get it to fit into my car without cutting up the tunnel. Even a 50% relief in the side of the tunnel will weaken it dramatically and I just didn't want to do it. But, if you have an E-body or '71-'75? B-body, I wouldn't hesitate to put in an A518 or A500.

Also, this conversion is really not a lot of work at all. Just making a trans mount for the A518 will be more work than what I had to do altogether. The hardest part is really cutting out the adapter that TCI should have done for me already. Borrowing a good band saw makes that job much easier though. Also, the cooling lines for the A518 are 3/8" so that you would need to upgrade your radiator cooler as well.

 

[rolling_Thunder]

If you ever want to let that 518 go... just saying. haha

awesome work