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joedoh 04-02-2022 10:58 PM

41-46 S10 swap
5 Attachment(s)
I have done two of these prior (look for fenix and hannah) and sold some hand cut mounts to guys to build their own, but then i got sidetracked making an easy-to-fold 47-55.1 weld on s10 swap kit and my patterns kind of fell by the wayside.

lately i have been getting questions and requests for the 41-46 swap stuff again and so i called my homie larry to bring his truck under the guise of doing his steering column and brakes but really so i could measure the mounts of mine he had on his truck. hey, everyone gets something from that, right?

then i needed a truck, another friend moved to florida for a contract job and rented his house, he needed a spot for his 46 so I told him he could keep it at my storage building for yard art. was pretty good for that!

i yanked it apart, believe it or not there are 10 bolts holding the cab on the frame, four under the front floor, two in front of the seat, and 4 behind the seat under the gas tank. there was obviously no expectation of rust because they suuuuuck to take out, no good place to even cut them.

I popped out some folding mounts using larrys dimensions and some much needed improvements and plopped the cab on for a look.

looked ok but for some reason the bolt holes did not line up, hmmm. I made a wider set and popped them on

hmm. i knew the lowest fender bolt hole to centerline of front axle is about 27", this was closer to 31. I think maybe larry shifted his cab back or maybe used the rear of those 4 front holes.

joedoh 04-02-2022 11:06 PM

Re: 41-46 S10 swap
4 Attachment(s)
i dug out the mounts i just cut off and this time used a magic device called a tape measure, this is how far the mounts were off.

much better.

working on the front clip, got a couple bolts in to see where the lower air director needs trimming. the front will drop an inch or two, once i do that and the wheel will be exactly centered, right now its juuuust slightly back

you can see the running boards will be about even with the bottom of the frame, thats the goal anyway. I know i can reuse the universal bed mounts I made for my 47-55.1 kit, maybe the running board mounts too, we will see.

joedoh 06-25-2022 08:02 PM

Re: 41-46 S10 swap
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the running board leg mounts will work but i redesigned the frame side to work better with both generations of truck and will make the kit changes for the later trucks and just use this design going forward.

the core mounts totally differently than the 47-55.1 though so there was no opportunity to reuse, so i designed a 100% bolt on core mount setup that will still fit in flat rate boxes for shipping on the cheap.

this was the last piece of design work, the bumper mounts work and so do the bed mounts, so once i proof the core mounts (spoiler: the design was mocked up on the truck already so should be fine) i can assemble the truck and put the column and pedals in and on the road it goes. well on the trailer.

joedoh 06-25-2022 08:08 PM

Re: 41-46 S10 swap
5 Attachment(s)
speaking of running boards, i have some neat info for you guys. the front clip came from a 1 ton, which i didnt think was a big deal because the wheel opening radius measured the same as 1/2 ton. but i couldnt get anything to line up!

I was pulling out my hair (god beat me to it) trying to see what was wrong and when I went through the archives i found the issue.

the vertical section of the running board is 2" taller! look under the door!

so instead of giving up (or more likely using the really destroyed 1/2 ton parts at the shop) I just sectioned 2" out of the fender bottoms and moved on with life

a friend and I were discussing it and this seems to be what they did in the 30s too, he has a 38 and a 40 with small wheel opening but taller running boards! so now instead of new fenders for his projects he can just section them too.

joedoh 06-30-2022 12:49 AM

Re: 41-46 S10 swap
5 Attachment(s)
running boards done, I need to put the bed on but thats kinda boring. what I tell everyone is mounting the body is easy, its the everything else that takes all the time.

brakes and steering are a big part of that. it doesnt matter if you are doing an s10 or a MII or any other kind of modern upgrade. its all the same thing.

on the 39-46 (same cabs, 40-46 have the same dash even) the dash should come out, thats easily done on these. there are two 7/16 at the lower corners, two 1/4" machine screws in the cowl vent lever, two acorn 3/8 on a center dash brace, and 6 clutch head acorss the front top of the dash behind teh windshield. if your steering column is still in you will have to remove the column drop, the top of it holds another brace. you may have to pull the gauges if your wiring is still in good shape, and the choke and throttle bowden cables will hold you up too. in this truck none of that is any good so a slicer blade made short work of it all. if your windshield is stuck like this one, you can sometimes get it open a tiny bit and get your slicer in there to cut the heads off the clutch heads, which lets be honest probably wouldnt come out anyway. the last thing to remove is the crank for the windshield once everything is out you pull at the bottom and lift, it will just pop off.

i put a straightedge in to know where the bottom of the dash is, and i mark the center of the gauges so I know where to center the column. on this truck it was 12" from the inside edge. you can make out the mark in my potato image.

I make a 5 dgree booster plate that serves to both mount the s10/later gm master cylinder at the correct 5 degree angle and also really stiffens the firewall. especially after its welded in because it doubles the thickness of the firewall, and the bends for the 5 degree also stiffen it.

I hold the s10 pedal assembly in place so that the steering column mount section is centered and just above the straightedge (i will explain why in a minute). I guess i didnt take a picture of that step but here is the result, you mark the firewall with the holes on the bracket then mark it with the edges of the 5 degree plate.

more next post

joedoh 06-30-2022 12:53 AM

Re: 41-46 S10 swap
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cut your hole, and fit the plate. you can see what a booger this would have been without the plate, with the x pattern in the firewall it would be hard to get the booster to mount flat.

test fits

looks good so far. before welding it iin lets set the column

more in next post

joedoh 06-30-2022 01:03 AM

Re: 41-46 S10 swap
5 Attachment(s)
to get the s10 column to fit you need to take off the bottom bracket. its welded to the tube and if you are careful you can grind gently till its loose and just slide it off. you will need to take off the bottom bearing retainer clip and retainer collar and if your bottom bearing is worn out its only 16 dollars to replace it now.

I decided to move the column in a couple inches from stock based on how small this cab is, in its original position it would be right in your gut even with a tilt column. easily done though. drill then extend the slot.

i also needed some bolts that wouldnt need to be held on top to tighten. on the s10 the pedal brace has the bolts in it but we arent using it so I got some nice bolts out of another aluminum steering bracket from a later s10 and gave them some meaty tacks. fully welding isnt needed, the clamping is what holds it, you just dont want them turning.

I build an upper bracket that bolts to where the original dash brace bolted on the firewall

more in next post.

joedoh 06-30-2022 01:13 AM

Re: 41-46 S10 swap
2 Attachment(s)
now cut a hole in the firewall for the bottom of the column with a 2.5" holesaw and I plan to reuse the stock firewall closeout (the one I just ground off!) just clocked to fit this firewall. test fit the column and make sure the angle is good to clear the pedals. when you are happy with it, put the dash back in.... and.....

mark the dash for the cut. i said i mock it up higher than the dash edge, and the reason is that if you go with a steep angle it looks like a bus column and if you put it as low as the column drop all the column and wiring is super visible. the dash isnt the only structure to hold the column any more. so you can trim it and not worry about structure. I use a 3" holesaw as the guide, cut it with a slicer to a rough shape and finish with a grinder to get a super nice cut.

cut a little at a time and keep fitting the dash until its good. when its time to reinstall the dash you will need to loosen the column to get the dash on the lower brackets and then tighten the column back up into the cut.

it looks like you are cutting so much but when the dash is in you barely even notice. this has a great fit now, the stickout is good on the engine side, it clears the pedals, its super duper great

oh and that picture of the column mocked up jsut higher than the dash edge IS up there, its the potato pic haha.

joedoh 07-04-2022 12:46 AM

Re: 41-46 S10 swap
5 Attachment(s)
pulled the cab for finish welding and some chassis black, lazy about it! left the front clip and running boards attached.

when i was pulling the cab i felt a stitch in my calf muscle, like when you stretch it for the first time in the day without stretching beforehand. nope, it was a wasp next I stirred up moving the a frame. a little liquid death and back to work.

putting the cab back on, check the alignment!

my 47-55.1 bed kit works perfect with just the smallest trim to the front two mounts, because the 41-46 bed is 48.5 inches width instead of 51". I also put in the third (front most) crossmember for strength, because I used an ext cab frame the mounts were still there.

good alignment!

more next

joedoh 07-04-2022 12:51 AM

Re: 41-46 S10 swap
5 Attachment(s)
more good alignment

front clip support rods to core support drilled and tapped. you can see that both the one ton core support and the 1/2 ton support rods both show remnants of farmer brazing.

I had to weld this rectangle tube to the core support and use leverage to get it lined up.

good alignment here too!

have to weld the front bumper mounts on in the morning, big gauge shows empty but the little gauge still shows gas, think I have enough to finish? :lol::lol:

delivery is thursday, then I will write up instructions. impressive 50% kit reuse, that will save some money!

joedoh 07-07-2022 02:13 PM

Re: 41-46 S10 swap
5 Attachment(s)
rolled out, ready for pickup. everything bolted down and happy.

rear bumper and front bumper mounts are on and good.

picked up more steel and the rest of the spare parts

this one is in the books, thanks for following along

Father&son56project 07-13-2022 07:20 AM

Re: 41-46 S10 swap
Awesome step-by-step instructions!

jrusher 08-16-2022 06:32 PM

Re: 41-46 S10 swap
Nice work! Which S10 frame did you use for this truck ? I might go this route for my 45

joedoh 08-16-2022 10:12 PM

Re: 41-46 S10 swap
i used an ext cab 123" wheelbase and took out 8" to make a 115 wheelbase.

if i can help you let me know!

jrusher 08-17-2022 04:26 PM

Re: 41-46 S10 swap
Yes will do thanks! I found a S10 frame with a 118" wheelbase yesterday $900 Im not too keen on scraping this stock frame though. Its clean and straight so thinking about the mustang II front kit or even a nova front end.

Originally Posted by joedoh (Post 9113513)
i used an ext cab 123" wheelbase and took out 8" to make a 115 wheelbase.

if i can help you let me know!

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