The official 6bt conversion thread

[Ranchero50]

Dustin, wht /red and red/wht are the water temp and oil pressure sensor leads, same as they older trucks. Not sure which is which from memory, but look at the block oil pressure sensor on the '94 for the correct one. Painless.

Jamie

[averagef250]

Switching bodies is 10 times more work than swapping an engine and tranny. The early bodies don't come close to matching the 80-97 frames and the early 4x4 frames are far stouter than the newer designed to crumple on impact frames. I'd see swapping under a newer frame (atleast a 4x4 one) as a major downgrade from the earlier ones.

The 4BT fits better in the '79 and older engine bay. There's actually more downpipe clearance and it sits further forward.

Thanks for the gauge colors Jamie! I got a little too excited and just sliced all the engine/ecu wires off, figured I'd pull them all out and whatever was left would be needed wires. There's a good number of "I wonder what that does" wires still there. Everything seams to work though.

[mljjones67]

Dustin is it a lot of work to get the mated transfer case in the highboy. What should I look for in a transfer case?

[averagef250]

Is your truck lifted or stock height? If it is stock height you can pull your old t-case and drivelines out, remove the old tranny crossmember and crossmember mounts, put the new ZF and NP205 in place and set the old crossmember on the lower lip of the frame, drill two new holes and bolt it in. Have your drivelines shortened/lengthened to fit, cut your speedo cable down a bit, T-case shift linkage from a 70's ford 4x4 with a mated 205 works well to bolt on the ZF. The divorced stuff works too.

If the truck is lifted you'll need to do all that and swap in a '78-'79 high pinion front axle for the front u-joint angles.

The t-case to look for is a mated 73 to 79 NP205. They were used in 73 to 79 F-150 4x4's with a 2 speed case and all 77.5 to 79 F-250/F-350 4x4's. You can use from an auto or manual truck. $150 is the going rate for one in perfect shape. $50 for a rebuilder.

Seams like a ton of work, but it's really not that bad. When your doing the 4BT swap the truck is all torn apart. It's not much more work to do the t-case and drivelines.

[xxxtina63]

Even though I like the idea of a 4x4, what about a 2wd? Attach a ZF or M5R2, move the crossmember if necessary, modify length of front section of driveshaft, and change third member to match diesel powerband? Like 3.08's or 3.23"s? Will "six" motor mounts still be an option? Also, what about cooling? Does an FE radiator have the hoses on the correct sides?

[averagef250]

I haven't swapped a cummins into an early 2wd. The motor mounts might be a bit tricky since you're essentially moving the 4x4 towers down 2.5" on each side, there isn't much room to go down that far with a 2wd. You may need to get the late model dodge 5.9 mounts to get a nice mount setup that works. You'll also need to build a tranny crossmember from scratch for the mazda or ZF tranny since it's mount surface is a couple inches lower than a 4 speed. I know it's been done, Seen a few local dentside F-350's with 5.9's in them, but haven't looked real close at the mounts.

The six radiator makes for the cleanest install. If you run the V8 one you'll have to half-ass some hoses.

[averagef250]

On a different note, I've been toying with ideas for the 5.9 mounting in my '70 recently and trying to come up with a good way to drop the engine crossmember 4" and think I've found it. The forward frame section is boxed where the engine mounts up and forward to the crossmember. I'm going to have some 1/4" plate broken into a "C" channel to replace the frame boxing that's already there. I'll very carefully remove the factory inner frame piece and crossmember and replace it with this channel. The new piece will be several inches longer and extend forward far enough that the new crossmember will bolt to it. I'm simply going to build the new crossmember from 3 pieces of 3/8" plate. I'll have the front and back burned to shape and I'll have one inner web piece burned with a few drain holes in it and broken to match the contour of the sides. I'll use four weldnuts or so in each side of the frame and make it bolt in from underneath. Should make oil pan removal a snap.

[Ranchero50]

Kinds like the early mustangs with the removeable crossmember

Jamie

[averagef250]

Yeah, just with a bit more beef than that piece of exhaust tubing with the ends flattened! 1/4 and 3/8 plate have got to be overkill, but another 100 pounds of weight in the frame isn't going to hurt anything. It's easier to fab thicker parts. They don't warp as much and when they do they're easier to flame straighten.

[mljjones67]

5.9 hmmmmmmmmm

[mljjones67]

It sure is interesting. The only thing holding me back is the 4bt. I think with it in the 67 it would be one odd but awesome truck. I would bet no one around here has one in there truck let alone a bump side. Also I like the idea of the 30 mile to the gallon possibility. I know the 5.9 would work harder and pull alot more, but the stuff I would have to do to get it in there makes it a little out of my skill level. the 4bt is going to be a stretch on my skill level as it is. I am hoping with the upgrades on the 4bt it will be enough for my needs. But you never know a 5.9 running on vegi oil would be awesome too. The most I would be towing would be my flat bed car hauler and maybe a bump or car on there once and a while. I think if my 5.3 Chebby motor can haul the bump the 4bt will be fine. I just like the idea of the 4bt. I need to get a parts list together on the 4bt swap and get going on it. I plan on selling the 2003 chebby half ton and drivin the bump. I have a place here that can convert my Tahoe to propane for about $2500.00 That is something I will looking into soon also. If we keep it? She wants a Escalade. So we might be converting it. Any help on my parts list would be awesome. I will post mine once I get one together. thanks Dustin and everyone else

[averagef250]

I've had guys tell me the 5.9 was real easy to fit in thier (insert POS old truck here), what it came down to is they weren't shy with the sledge and cutting torch. A nice install is a TON of work. Personally, I've even seen the work of Ford-cummins.com and thier stuff is crap. I would never put my name on some of the stuff they've turned out. I'm really suprised how they claim to be such experts at cummins swaps while thier mounts and conversion parts seam to have a complete disregard for correct drivetrain angles and cause major clearance problems.

[mljjones67]

I am going to stick with the 4bt. Seems easier and what I will get out of it will be worth it!!

[mljjones67]

Here is my list. Please let me know how much I miss!!
1: 4bt cummins engine
2: Ford bell housing
3: 300 6 engine stands
4: Engine mounts from a 79-80 something
5: ZF S542 out of 87-97 f-250 or f-350 ,or Dodge NV4500
6: Mated t-case
7: 4:10 rear gears.
8: welding cable to hook from battery to starter.
9: Sensors off 352
10:Shifter linkage off 352

[averagef250]

Sounds good. The "ford bellhousing" is actually called a block plate. It's just a cast aluminum plate that bolts the rear of the block. You'll need the flywheel to match it as well. Not 100% sure, but I have heard that all 4BT flywheels for 12" clutches are the same for manual transmissions. Meaning whatever block plate a 4BT has, if it's for a manual tranny the flywheel will work with a ford provided you can fit the Ford pilot bearing in it.

The FE frame towers your truck has will work fine if you can't find 300 six ones. You just need to move them up to the forwardmost set of frame holes and you will have to drill two new mounting holes in each stand to completely bolt them in.

The ZF 5 speed must be the small block bellhousing version, count the output splines to be sure it has 32 splines.

May want to add the tranny hump cover from an auto bumpside or dentside. If you can find one for nothing it makes moving the shifter location back a couple inches easier.