Extending a FJ40 Frame? (1 Viewer)

[CHCP]

I posted this message last week on the general FJ40 tech forum without any replies maybe you folks can give me some feedback, thanks

I recently posted a sweet looking 45swb with a flat bed made by Gary Kardum several years ago, since then he has modified it because of excessive weight. I want to make one. But I do not have a 45swb frame. I do have a really good 63 FJ40 frame. The 40 wheel base is shorter by 14.3 inches and the frame is shorter by 27.9" so I'm trying to estimate how long I can make the bed. The 45swb has a frame that extends 21.65" past the rear leaf spring hanger and on the 40 the end is at the hanger. Would it be safe to assume that the 40 frame could be extended this same length without affecting drivability? I was wondering about the effects on wheel caster but it doesn't seem that caster is much effected by moving the vehicle's center of gravity, or does it? I looked at photos here on mud and the internet and it looks like the rear pickup body mounts on the frame between the mid cross tube and the rear leaf spring perch, since these have the same dimensions on a 40 and 45swb adding the 21.65" extension it looks like I could have a flat bed (minus the distance between the flat bed and rear pickup cab) of about 73". Opinions and input would be good. Thanks

 

[cult45]

You wanna make the bed or stretch the frame? Sorry man, your question is a little confusing.

 

[CHCP]

I am thinking that the bed needs to be the same length as the frame for structural strength. You bring another train of thought, instead of extending the frame, extend the bed beyond the frame. I'm trying to get a handle on weight distribution since the swb had a 104" wheel base and the 40 has 90". Should I try this with a 40 or wait until I can find a 45 swb frame. I don't want a long bed something close to 6' would fit my needs. Sometimes with cruisers I have six trains of thought going at once guess that"s why I'm into them.

 

[cult45]

If you use a 40 frame all the weight distribution will be wrong, or Mr. Toyoda would have just made 90" WB trucks for every appilcation instead of spending big on making LWB trucks. So you'll need to either run a very short bed on a SWB chassis, or wait for an FJ45 frame or stretch an existing FJ40 frame.

If you wanna wait for a 45 SWB frame then go for it, but it might be a while. If you're going to stretch a 40 frame, don't use the 1963 one - it's too rare. Start with a later one. Gary Waggoner did a good write up with pics when he shortened the frame on an 80 series to suit a 60 series body in Project X2. The chassis was so strong after the cut that it survived a massive car accident and everyone walked away.

Or alternatively, get yourself some modernity about the truck and use an 80 frame? A friend of mine found an 80 frame, ground the body mounts off, detached the 45 body mounts and then welded them on the 80 frame. Said all in all it took two days.

 

[CHCP]

Thanks cult45 for the input.
A part of my brain was telling me not to mess with the 63 since I have the matching f engine and 90% of the original body parts including the hardtop.
I may have to wait for a 45swb frame. Cruiserparts.net have some 45 frames for sale, I don't know if they are 104s or 187s. The price seems a bit steep at $2500.
and by stretching a 40 frame you mean to increase the wheel base from 90 to 104 not by extending the rear, correct?
So its becoming a longer term project. That's ok because I was thinking about a diesel power plant. I see you have some diesels, I'm thinking either Toyota 3B, Isuzu 4BD1T or a Cummins 3.3 any recommendations?

 

[cult45]

Yeah man, stretch it in the middle. Find a schematic on a 45 frame and go from there. Don't you think it'd be weird with all that overhang at the back??