: 4BT in a '90 f 150

01-13-2007, 07:24 AM
1990 F150 super cab 4X4. Am going with a ZF5 trans, BW 1356 transfer. I may change the rear 8.8" to 10.25" Sterling and convert the front D44 TTB to 8 lug using Chevy knuckles and spindles. 16" wheels with probably 295/75 tires. Probably a 2 or 2.5" lift. With 3.08 gears it will be turning 1700 at 70 mph. No real serious off road or towing. A complete body off resto with maybe a front clip from a mid 90's. I'm going to try an HY35 turbo with a slightly turned up pump with air cooler.

04-29-2007, 01:25 PM
Hey Man

Was just wondering how the swap was going. I just found this website and I am just reading up on this stuff. Would like to know more.

By the way I have a 89 Bronco that I might convert.bounce


05-13-2007, 06:12 AM
Well, it has not progressed as fast as I had wanted due to some other stuff going on. I've decided on some changes, I want to do a straight axle swap using a '79 D44 front and want a Ford 9" in the rear. Same 3.07 gears but 9 x16 (36" OD) STA Super Lug tires. 5th at 70 will give about 1560 rpm's. On secondary roads or loaded I can run in 4th at 1760 @ 60.

06-11-2007, 08:45 PM
Hey 52wrench

Good to hear you are still working on your truck. It seems to me that those rpm's would be low to me. I think my final rpm range if I were to do mine would be in the 1750's or 1800's doing 70 mph. But its your rig. Then again I could be totally off. I would second the notion with going to a solid axle. That TTB wont last long.

Keep us updated.


06-12-2007, 05:54 AM
AUBronco - Yeah, I just got done reading the thread on mpg/gearing, maybe the 1560 @ 70 will be too slow. But then a couple guys said it really sounds nice at 1500. I've got some time to think about it as I just got the 4BT bottom end together. Then I have to rebuild the ZF5 before I start tearing the truck apart. Been playing with the Harley too much lately.

06-12-2007, 09:50 PM
Hey 52wrench

Well dont let me change your mind I was just pointing out that some of these guys were saying that these engines like to run in that 1700-1850 maybe 1900 range is there sweet spot. I had two 6 cy cummins and both of them got nice performance and gas (actually it would diesel) milage at running about 1900 rpms.

I hear you about working on your Harley. This Bronco is my play truck and I am debating on whether or not I should take it on.


06-26-2007, 12:36 AM
I recently put a 4BT into a '94 F-250 4x4 to replace a 4.9 six. Bolted it right to the M5R2. The mounts bolted right in. Wiring and fuel system was very easy. Total swap time took maybe 15 hours over 3 days. The M5R2 with 4.10 axles and 35" tires makes for a very nice gear spread, much nicer than the granny 1st small block S5-42.

06-26-2007, 06:32 PM
What is the M5R2? I have not heard of it.


06-26-2007, 11:41 PM
The M5R2 is the bronco/f-150 5 speed ford has used since '88. Full synchro, close ratio 5 speed. They've got a bad rap for breaking, but it's not usually from power. Most die from low oil or the wrong type of oil. A heck of a lot cheaper to buy and fix than an S5-42.

06-27-2007, 12:39 AM
Good to see ya over here Dustin

06-27-2007, 11:25 AM
So is that the Mazda transmission?


06-27-2007, 11:40 AM
Hey Mike! There's some good stuff here! Reading some of the posts here, I think I know a few more of these guys as well.

Yes, the M5R2 is the Mazda built 5 speed.

06-27-2007, 06:33 PM
Definatly a cool site. I like all the new ideas and tech they have here!!

09-09-2007, 02:26 PM
Some pics:

09-09-2007, 02:34 PM
More pics. The mounts aren't finished yet. Need to complete welding on driver's side and make spacers for passenger side to mid-mount holes along with cutting clearance for coolant elbow and turbo drain.

09-09-2007, 02:41 PM
Vehicle before entering surgery. Total restoration. Box is getting scrapped, aluminum flatbed to replace it. Also repalcement D44 front and 9" rear going in.

09-09-2007, 06:05 PM

Give details please. Still trying to get my stuff striaght before I dive into this. Trying to get all the parts so that this will go easier. Did you have any clearance problems with the firewall. What are your plans for the rest of it.


09-09-2007, 08:39 PM
No probs at all with firewall or tunnel clearance, keep in mind this is with the M5R2 tranny. I don't think the ZF would be a problem though. I used the stock tranny crossmember in the stock location. To couple the tranny to the 4B I used the Ford flywheel housing from a p30. Next step is to get some heavier and longer front coils, fab some radius arms for the D44 and get it and the 9" rear mounted then work out the driveline alignment before I finalize engine height. Then remove cab, sand blast frame then I am going to fishplate both frame runners on the outside with 1/8" plate so if I ever want to make this into a 3/4 or 1 T with D60's I'm not concerned about frame strength. Also there was a moderate amount of corrosion. I am going to run 3.07 gears with a Detroit Locker in the front and probably an Eaton limited slip in the rear, reason being the front is where the weight will be over the locker. Rock Crawler steel 16'" wheels. I am still debating tires, what I really want is Denman 305/85 R16 Coyote A/P 10 plies. They show up in there 2006 catalog and I read on TDR that you can get them from Nat'l Tire so I'm calling them tomrrow. If I can't get the Denmans then probably use STA 9.00 X 16's bias or Power King 9.00 x 16 bias. I want a tall but narrow tire. Once the chassis is done then I'm putting a front clip from a mid 90's on and cut out the rust on the cab and weld in repair panels, then paint. The box will be scrapped for a flatbed, either aluminum frame with aluminum diamond plate bed or alum. frame with hardwood bed, haven't decided yet. I may stick one of those lightweight pop top campers on in the future for travels into northwest territories, BC, Alberta and Alaska. If the 3.07's are too high for that use then I'll put on some smaller diameter tires. With the 3.07's and 9.00x16 tires it should turn 1680 in 5th with the M5R2 and 1600 with a ZF5. If I go with a camper I'd probably stick the ZF5 in it with 275/75 r16's which will put it at 1800 in 5th at 70 and 1860 at 60 in 4th. But I'm a long ways from that.:)

09-12-2007, 12:37 PM
Sweet swap man, Im going to be doing the same in an 89 F250 with a 300-6. Good luck with the swap and KEEP US UPDATED!!

10-02-2007, 06:21 AM
Frame is out, TTB front end is off, sand blast next step then start beefing up the frame.

10-02-2007, 11:44 AM
Why not start with an F-350 frame or just bolt a 66-79 Dana 44 under the front of the truck if you want a straight axle? In the grand scheme of things it surely seams ten times simpler and cleaner to either stay coils with a 44 solid axle or go to a leaf frame and a Dana 60. To me, The 4BT is pretty light and doesn't make much power. The 250/350 suspension and a 60 front seam very overkill unless you really beat the truck.

You can even bolt 8 lug outers on the solid 44 front to match a sterling rear if you don't like the 8.8.

94 and up cummins dodge frames break all the time. Can't say I've seen or heard of too many 80-97 Ford frames having problems. Plating the frame is a lot of work that might not be necessary.

10-02-2007, 07:55 PM
That's what I'm doing, putting a '79 D44 straight axle under it, as seen in one of the pics above, along with a 9" rear. The frame has some moderate corrosion in spots. any other frame I get around here will probably be the same or worse, I oiled this frame a few times over the years and it helped but the salt just eats things up around here.

11-13-2007, 09:37 PM
... To me, The 4BT is pretty light and doesn't make much power. The 250/350 suspension and a 60 front seam very overkill unless you really beat the truck.

You can even bolt 8 lug outers on the solid 44 front to match a sterling rear if you don't like the 8.8.

Was thinking of similar project with my 92 Bronco - since it is basically a shorter F-150, would you think the 4BT to be underpowered for similar application?

If not a 4BT, what would be slightly better?

TAZ bounce

12-15-2007, 02:57 PM
Just to let you guys know I'm still around, here's a shot of my frame after I got it back from the hot dip galvanizer. I boxed it from the front cross member to a little past the forward rear spring perches. The frame for the flat bed will stiffen the rest of it. Now to start reassembling it then start on the axles.

12-29-2007, 10:50 PM
Been going round- n-round on gearing, finally figured the way to solve it is to put the Gear Vendors OD unit that has been collecting dust on to the 1356 t-case. I'll run 3.73 gears and the gasser ZF5. The GV unit will give me 9 usable forward gears with a clutchless full throttle shift between each manual gear change from 2nd on up. 5th over, which will be a double over, will give 1670 @ 75 for running unloaded. For towing or hauling, I can run 4th over for around 2050 at 70. I'll get the better acceleration from the 3.73's but still have a very nice cruise rpm. The gear spread works out to: 1st 5.73, 2nd 2.94, 2nd over 2.29, 3rd 1.61, 3rd over 1.26, 4th 1.00, 4th over .78, 5th .76, 5th over .59. Don't think I can use 1st over since the minimum speed for engaging the GV is 20 I think but have to verify.

12-29-2007, 11:51 PM
You won't be disappointed with more gears. You can get the most out of a 4bt in the right rpm range. Why is there the minimum speed for operating the GV? What model or year is it?

12-31-2007, 01:59 AM
i don't that it's an issue with speed, i think it's to do with the amount of torque multiplication in the lower gears.

01-01-2008, 04:28 PM
The GV has it's own oil pump to supply oil to the bearings and to supply oil pressure to the cone clutch to lock it in OD. My understanding is that under 20 mph or so the pump doesn't make enough psi to positively lock the clutch. Its not really a problem because 2nd is normally used to get moving anyway on the street except when heavy towing. The GV can't be used in 4x4 since it goes on the end of the T-case.

03-25-2008, 05:26 AM
Finally got some time to work on this. Got the frame back together after the hot dip. I plated the front and rear of the rails with 1/8", beefed up the rear spring perches and a few other things. It is strong. Next job is rebuild the 9" rear and get it installed.

03-25-2008, 05:30 AM

04-07-2008, 08:56 PM
Hey, Just wondering how the rebuild is going? I have a 90 F150 and am looking either a 6BT or 4BT conversion. Like the 6BT for the power but like the 4BT for the milage.


06-03-2008, 05:41 AM
Hey, Just bringing this back to the top, I hope the original poster has some updated info, looks like the build was getting off to a very good start.

Hope to see it through to the end!

06-06-2008, 12:28 PM
Wow! So a 4BT bolts right up to a Ford/Mazda M5R2? Can you retain the factory hydraulic clutch slave cyl and TO bearing? That would be great. I was considering a Isuzu 4BD1/2T swap in my 2001 F150 with the M5R2 but can't get any info on trans adaptors. Pls tell me what kind of clutch you used, because the Ford factory piece is weak, even behind the 4.2l V6 gasser. Thanks, Dean

06-06-2008, 07:51 PM
You need the small block/six M5R2 not the modular version for the regular ford 4bt adapter.

All the ford clutch components work fine.

06-06-2008, 10:48 PM
how much does it cost to hot dip the frame

06-14-2008, 06:16 AM
Its been awhile. had some other stuff going on last few months so this project is taking longer than planned, surprise, surprise. Anyway, here is where I am at present. I've got all the mechanicals done on the Ford 9" rear, 3.50 gears with Eaton Truetrac diff, new set20 bearings on the shafts, etc. The '79 D44 front diff is also done, again with Truetrac diff, 3.54 gears. Next step is modify the late 90's Explorer rear disc setup I got from a yard to mount to the 9" ends, will have to redrill rotor bolt pattern to 5x5.5. Rear springs are done with new bushings, one new leaf on each side. Then get the rear temporarily mounted. The stock radius arms for the front D44 were cut at yard 1' behind axle so I am going to fab new arms using them to attach to axle and with 2 1/2" Currie Johnny Joints at the frame. Johnny Joints are in transit now. I still need to mount the front coil towers to the frame and get the 4" lift coils and axle in with engine/tranny sitting on mounts before I can start on the radius arms and to check the D44 to engine crossmember clearance. Also may need to mod/fab trans mount to get front driveshaft to clear the mount. Once I have a rolling chassis and appears all will work take it all apart for paint, wash primer with epoxy primer over that then chassis black. To the last question, the hot dip was $250.