Pete Whitstone Posted June 23, 2021 Share Posted June 23, 2021 Hi All, one of my long term goals for my 81 SWB flareside is to convert it to 4WD (please don't tell me I should have just bought a 4WD truck in the first place). I'm not entirely certain of the chassis it currently has. The VIN on the cab decodes as a 81, but it does not have the swiss cheese frame, and I cannot locate a VIN on the frame, despite having looked several times. For the sake of this conversation, let's assume it's an 82-86 non-swiss-cheese Gen 7 frame. Or maybe it's truly an 81 and not all 81's were swiss cheese, I simply don't know. So with that in mind, I have been watching FB marketplace, Craigs list, etc., for 4WD donor vehicles. Here's where my familiarity with the truck gets a little thin. I think a donor vehicle from 80-86 would be completely compatible. And I don't think they changed the chassis much from 87-91, so I'm guessing that a donor from those years would work too. After that, I'm unsure if the chassis changed substantially. I see a lot of parts that say that are compatible with 80-96, so is a chassis from 92-96 going to be a suitable donor vehicle? What about Bronco's - is is basically the same chassis and should swap over easily? What years of Bronco's? I am mostly concerned with things like the chassis mounting point for the trans cross-member, suspension mounting points, and things like that. While I'm on that subject, what's up with some trucks being upper/lower ball joints, and some being kingpin? Mine happens to be ball joint, but what trucks came with kingpins? F250 and above or something? Is it a requirement that the donor vehicle also be a SWB truck, or will a LWB truck work and it's just a matter of shortening the rear drive shaft? Anyone out there done this? What are the potential pitfalls and gotcha's? Thanks! Link to comment Share on other sites More sharing options...
salans7 Posted June 23, 2021 Share Posted June 23, 2021 Kingpin trucks are as follows: 1980-1981 F100 1980-1981 F150 4x2 1980-1986 F250 4x2 1980-1986 F350 4x2 1986-1991 F350 4x4 Everything else used ball joints. 1987-1991 trucks used an almost identical frame to the 1980-1986 trucks. However, the front bumper mounts differently on the 87-91 (they mount to the side of the frame rail via angle brackets) and I've seen some 87-91 frames that do NOT have the slotted holes in the front of the frame rail for the 80-86 style bumper. I have also seen some 87-91 trucks that do have both sets of holes, so just keep it in mind. 1992-1996 frames have different front frame horns, and are not at all compatible with 80-86 bumpers. Rembrandt, a member here, used a 92-96 frame on his 1980 F150. He grafted the 80-86 frame horns onto the newer frame. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted June 23, 2021 Author Share Posted June 23, 2021 Kingpin trucks are as follows: 1980-1981 F100 1980-1981 F150 4x2 1980-1986 F250 4x2 1980-1986 F350 4x2 1986-1991 F350 4x4 Everything else used ball joints. But, my truck is (ostensibly) an 81 2WD, and does not have kingpins. So is that proof that my frame is not an 81? Bumper mount concerns aside, are the 92-96 suspension, engine and trans mounting points the same as an 81 (or maybe an 82-86)? Link to comment Share on other sites More sharing options...
salans7 Posted June 23, 2021 Share Posted June 23, 2021 Kingpin trucks are as follows: 1980-1981 F100 1980-1981 F150 4x2 1980-1986 F250 4x2 1980-1986 F350 4x2 1986-1991 F350 4x4 Everything else used ball joints. But, my truck is (ostensibly) an 81 2WD, and does not have kingpins. So is that proof that my frame is not an 81? Bumper mount concerns aside, are the 92-96 suspension, engine and trans mounting points the same as an 81 (or maybe an 82-86)? If I remember correctly (it's been years since I was reciting this info on another forum), the swiss cheese frame was a mid-year change out in 81, as were the kingpins. I think it's definitely possible that a late build 81 could have a traditional frame and ball joints. For what it's worth, the vin on my 1980 F150 was stamped on top of the frame right near the heater box. It was in the same spot on my 1986 F250 parts truck. Engine, transmission, and suspension mounting is basically the same from 80-96 when it comes to the 1/2 ton trucks. So no worries there. I 4x4 swapped my 1980 F150 using 1995 axle halves, 1984 steering knuckles and spindles, a 1982 transmission crossmember (4x4 crossmembers are different than 4x2), and 1989 axle shafts. Everything worked together without issue. Link to comment Share on other sites More sharing options...
Rembrant Posted June 23, 2021 Share Posted June 23, 2021 Kingpin trucks are as follows: 1980-1981 F100 1980-1981 F150 4x2 1980-1986 F250 4x2 1980-1986 F350 4x2 1986-1991 F350 4x4 Everything else used ball joints. But, my truck is (ostensibly) an 81 2WD, and does not have kingpins. So is that proof that my frame is not an 81? Bumper mount concerns aside, are the 92-96 suspension, engine and trans mounting points the same as an 81 (or maybe an 82-86)? I remember going through this with somebody else not all that long ago, but I think the 2wd changeover from kingpins to ball joints happened in the last production month of the 1981 model year, so it is possible to have a ball joint front end in an 81, IF it was built in the last month. I think… Do you have the stamped steel I-beams? Are they hollow? Or solid? Front bumper issues aside, yes the 1992-1996 frames are basically the same as 1980-1991. I had to drill a couple extra holes for the rear most mounting bolts of the Flareside bed, but that was about it. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted June 24, 2021 Author Share Posted June 24, 2021 Do you have the stamped steel I-beams? Are they hollow? Or solid? Thanks for the info, guys! The I-beams are solid, they appear to be a forging. What does that tell us? I think I remember seeing somewhere when shopping for ball joints about an 8/81 cutoff, so I think there may have been a very short window in the 81 model year where ball joints were used instead of kingpins. One donor truck I am looking at is a 95, it has a 351W (which I think would be a hydraulic roller motor), and what the ad describes as a "4D03" transmission - I think the seller means an E4OD. So that is an electronically controlled C6 with an overdrive, as I understand it. My question there is, is the trans controller separate from the engine controller? In other words, can I plug that transmission behind my carb'ed 351W running the trans controller only? If they are all one unit, I would either have to run the full 1995 engine/transmission package (I'm not entirely averse to FI), or see if someone makes a stand-alone controller for that trans. Any info appreciated there. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 24, 2021 Share Posted June 24, 2021 Do you have the stamped steel I-beams? Are they hollow? Or solid? Thanks for the info, guys! The I-beams are solid, they appear to be a forging. What does that tell us? I think I remember seeing somewhere when shopping for ball joints about an 8/81 cutoff, so I think there may have been a very short window in the 81 model year where ball joints were used instead of kingpins. One donor truck I am looking at is a 95, it has a 351W (which I think would be a hydraulic roller motor), and what the ad describes as a "4D03" transmission - I think the seller means an E4OD. So that is an electronically controlled C6 with an overdrive, as I understand it. My question there is, is the trans controller separate from the engine controller? In other words, can I plug that transmission behind my carb'ed 351W running the trans controller only? If they are all one unit, I would either have to run the full 1995 engine/transmission package (I'm not entirely averse to FI), or see if someone makes a stand-alone controller for that trans. Any info appreciated there. I'll let the others continue to answer questions re the suspension, but the E4OD's controller will be the EEC computer that also runs the EFI. So unless you are going with full-blown factory EFI then I don't think that is the controller for you. I've heard you can run the factory EEC from a diesel truck, I think for a 7.3L which wouldn't have had any/much electronics. Or you can go with an aftermarket controller, like a Baumann, but they cost ~$750. Having said that, I think the E4OD is a big improvement over a C6 as it has both the overdrive and the lockup torque converter. Link to comment Share on other sites More sharing options...
Pete Whitstone Posted June 24, 2021 Author Share Posted June 24, 2021 Having said that, I think the E4OD is a big improvement over a C6 as it has both the overdrive and the lockup torque converter. Yeah agreed, my mileage is pretty miserable, somewhere around 10-11. I thought that was low, but I looked it up and that's pretty much what they were getting in 1981. The 95 I am looking at shows 14/18 with a combined rating of 16. That's probably about what my 2006 F150 with the 5.4 gets. So would definitely consider swapping the entire drivetrain. I bet the 95 version of the 351W was putting out better power/torque numbers as well. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 24, 2021 Share Posted June 24, 2021 Having said that, I think the E4OD is a big improvement over a C6 as it has both the overdrive and the lockup torque converter. Yeah agreed, my mileage is pretty miserable, somewhere around 10-11. I thought that was low, but I looked it up and that's pretty much what they were getting in 1981. The 95 I am looking at shows 14/18 with a combined rating of 16. That's probably about what my 2006 F150 with the 5.4 gets. So would definitely consider swapping the entire drivetrain. I bet the 95 version of the 351W was putting out better power/torque numbers as well. With the donor it shouldn't be too bad. And you can't beat EFI. Even if the '95 is EEC-IV it would still be much better than a carb. Link to comment Share on other sites More sharing options...
Rembrant Posted June 24, 2021 Share Posted June 24, 2021 Having said that, I think the E4OD is a big improvement over a C6 as it has both the overdrive and the lockup torque converter. Yeah agreed, my mileage is pretty miserable, somewhere around 10-11. I thought that was low, but I looked it up and that's pretty much what they were getting in 1981. The 95 I am looking at shows 14/18 with a combined rating of 16. That's probably about what my 2006 F150 with the 5.4 gets. So would definitely consider swapping the entire drivetrain. I bet the 95 version of the 351W was putting out better power/torque numbers as well. I have a 1995 frame in my 1980 Flareside. The Bullnose front bumper swap has been done a few different ways, but I personally chopped the front ends of the 1995 frame off, and welded in Bullnose frame "horns" to mount the front bumper: The only other issue I ran into was the very tail end of the frame only has one set of holes for the bed, and the Bullnose frame has two sets of holes (the second set is only for the "old" Flareside bed, which didn't exist in 1995). I drilled the extra two holes and bam, done. There was also one small "flare" I will call in the 1995 rear most crossmember...I don't even know what it is for, but it interfered with the Flareside bed rear sill. I gave it a couple smacks with a hammer and made some clearance...haha...the frame, not the bed. So my truck is a 1980 F150, with a 1986 300 inline six, sitting on a 1995 F150 chassis with the 1995 5spd, axles, differentials, etc. Link to comment Share on other sites More sharing options...
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