Cummins 4BT to C6 flex plate, fly wheel and wave ring

Wow, that's very ugly. Does the van have the small block Ford adapter plate? OK, here are the part numbers for the original assembly shown below. You may already have some of these but I'll list them.
1 3901935 Hex Bolts (8 required)
2 3907701 Crank Adapter
3 3908124 Wave Ring
4 3904361 Clamping Ring
5 3900665 Hex Bolts (6 required)
6 3918957 Flex Plate
These parts are also found as a kit under part FW9043. Hope your dad has a strong heart because there's nothing cheap in those parts. The flex plate is around $400 and the wave ring is in the $300 range. Hopefully the crank adapter is OK because that puppy is over $400. The clamping ring is the only cheap piece of the puzzle at around $15. One note, member Rube Bonet (Rob Bonney Fabrication) makes a replacement for the wave ring. May not be much cheaper but it's about 10 times as strong. With all that mangled mess I assume the torque converter is getting replaced too. Part of the problem could be the wrong lockup on the converter. The 4bt likes lockup around 1300 RPM where gas models are a lot higher.

Hello Geebs. OK, if you plan on using the C6 you have some thinking to do. First off, you won't have an OD gear so your road speed will be very limited unless you have some very high ratio differential gears. If your truck is geared around 3.55:1 your top speed will only be around 55 MPH with stock governor speed. Are you looking to use a 4bt or 6bt? The part number FW9043 is a kit made by Cummins and sold by Cummins dealers. It was originally designed for the 4bt used in Chevy vans but can also be used with the Ford adapter plate. Now here is where you have to do some serious thinking. It is the cost. The first part you need in this puzzle is the small block Ford adapter plate which is part 3912601. Unless you can find a used one Cummins charges $1502.55 in the US for that piece and God only knows what it would cost in your area. That is for a totally blank plate and there are a few additional parts in that piece. Here is the complete list for that piece only.

3912601 Transmission Adapter $1502.55
3920447 M12x1.75x40mm flange head bolts 8 required $7.02ea (you may reuse old ones)
3908095 Cover Plate $8.72
3912072 M8x1.25x21mm self taping screws 2 required $5.13ea
3904181 Threaded plug $9.64
148582 Dowel pin 2 required $11.83ea
3910260 O ring seal $7.40
3910248 O ring plug $14.05
3934080 Starter spacer $294.22
3910901 M10x1.50x55 starter bolts 2 required $11.10ea
3957594 Starter $663.44
This just for the adapter plate and starter. Now for the FW9043 which is no longer listed so you buy it piece by piece.
3901395 M12x1.25x32 Flange head bolts 8 required $6.80ea
3907701 Crankshaft adapter $457.78
3908124 Torque converter adapter (wave ring) $390.32
3904361 Clamp ring $Price unknown probably around $20.00
3910665 Hex bolts 6 required $16.73ea
3918957 Flex plate $422.33
As you can see you're at a tad over $4000.00 just to attach the transmission to the engine. On top of this you need a 6 bolt torque converter with diesel stall speed around 1300 RPM. The one that came on the '85 F250 diesel with C6 might work but there is another wrinkle in the plan. The C6 that came on diesels had a different shifting system than the gas models. To my knowledge, we've never had anyone use a gas C6 behind a Cummins. All the Ford automatics that have been used were the E4OD which is the C6 with overdrive and computer control and the better replacement for that was the 4R100 which also came behind diesels. You can see why most of our swaps have been manual transmission. I checked the Destroked site and they show a flex plate for the C6 but it is for a big block version. They show a small block adapter plate but no corresponding flex plate. They may have it but don't show it. If they had one their system would be much cheaper than Cummins. Adapter plates run $795, flex plates $625, and 6.0 starter $190. So their system would be less than half the cost if available.

The question would be what you have available where you are. The common swap automatic transmission here in the US is either the Dodge 46RH or 47RH that came behind the Cummins. The "H" means hydraulic control so no computer involved. The 46RH has overdrive where the 47RH has overdrive and a lock up torque converter. You have to rig up switches to control the OD and lock up on those but no computer module. Do you know what injection pump is on the 4bt you're looking at? There are sensors that are needed on the engine for the transmission. Nothing simple about mounting an automatic. The 46RH came in '91.5-93 Dodge Cummins and 47RH in '94-95. After that all transmissions were RE which are computer controlled. If you went with a Dodge transmission you run into the issue that the output shaft doesn't match the input on your transfer case so an adapter is required. Advance Adapters makes those. Most all other automatics are computer controlled. Unfortunately, it's like you live on another planet when it comes to getting parts to you. I'm very much a Ford person and every truck we've had in our family has been a Ford starting with my dad's 1951 F1. I learned to drive on that one. There is another option on the C6 that I'd forgot about. A company here in the US named Phoenix Casting and Machining makes adapters to join regular transmissions to SAE flywheels systems. Probably much cheaper than the others I mentioned but still have the problem of no OD gear. Odds are that any 4bt you find will have an SAE flywheel adapter. The words being on a budget kind of go out the window when dealing with a Cummins and automatic transmissions. If I wanted to do an automatic in a Ford I'd probably select the 4R100 that came behind a 7.3 diesel. Replace the shift solenoids just as a mater of general maintenance and hope the clutches are in good shape. Rebuilding one of those tends to be quite expensive. Then use the Destroked adapter setup and an outboard computer controller. The controllers aren't horribly expensive. That transmission would bolt direct to your transfer case. Have you considered changing to a manual transmission?

Ok, had to do some more research before replying to your last comment. Thank you once again for the invaluable information. Here is what I've managed to come up with: Searched for 47RH (as I'd prefer the the lock up) over here but came up with nada. I did find a recoed 4R100 for $5695 delivered, but unable to find an adapter kit here, Destroked appear to have them, but was wondering if you know where I can get a complete kit from (as I'm not sure of everything needed). The 4L80's are not easy to find either & very expensive. I could only find two recoed, one was a 'Remanufactured Shiftright Street & Strip H/D 4l80e '91- '97 Automatic Shift 100 (1000HP)' with no torque converter for $5,350 pick up. The other was an 'Extreme Rebuild GM 4L80E 1200nm 4 Speed (includes Torque Converter)' for $6,455.25 + freight??? This company also had a complete 'Engine Adapter Kit to suit Cummins 4BT, 6BT, 12 Valve & 5.9 24 Valve 'Non Common Rail' to 4L80E' for $2,517.50 + freight. I did however find a 47RH on Ebay in Florida form 'Danny's Transmissions' who apparently ship worldwide: '47RH 47RE 48RE Dodge Diesel Transmission Stage 1 2wd or 4x4 Fits 1994-2003' with Billet Extra Heavy Duty Single Disc Torque Converter for US $2,971.35 + US $795.00 Standard International Shipping or approx. AU $5449.79, which would be my preferred option (as long as they're legit ..... they appear to be) due to the hydraulic control and the price, but I have so far been unable to find a shift kit to suit & was hoping that you might be able to help me out with that if possible ..... Oh yeah and the 4R100 is the other preferred option if there is an adapter kit available ...... and by the way, my F250 isn't a 4WD.

OK. If the 4R100 you found is from a Ford 7.3 diesel, you need about 4 parts. Destroked has the engine adapter plate $795, flex plate $625, 6.0 starter $199, and 2 different models of computer controllers which are $649 or $1034. You'd need to contact them to verify that you don't need anything else and what the shipping cost would be. Those prices are US $. Of course you will also need a torque converter to match to the engine. Prices on those can go all over the board. With the 47RH you will also need the Dodge Cummins engine adapter, flex plate, starter, and torque converter. There is also a sensor that mounts to the injection pump so not sure what's going to be involved there. In the Dodges, that transmission only came in 1994 and 1995 on engines with the P7100 injection pump. It also came on the 8.0 gas engines. You wouldn't want that one because the shift point were different than a Cummins. You also have the issue there of needing an adapter to mate to your transfer case. Just no easy fix for this.