Swap 8.5 IFS for 9.25?

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Supercharged111

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Get some pics of how it misses. I've also been curious about the 2 mount bolts on the right side.
 

98chevy2500SS

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The difference in the mount positions is that the mounts are further apart from each other, whereas the half-ton mount's are closer to each other. Can't remember the measurements at the moment, sadly. :(
 

98chevy2500SS

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Well guys, conversion complete!!! Took us a little under a month of weekends and it's finally finished. Took us mid August through the last week of August.

You will need to look at a 3/4 ton front mounts closely, basically look at a 3/4 ton very closely in general <-- I CANNOT STRESS THIS ENOUGH. Both mounts will need to be positioned back and up, since the 3/4 ton frames are indeed taller. For the front diff, you will need to add an extension on the bottom bolt where the skid plate mounts in the back, it will need to be about an inch or two lower since the diff is bigger and goes farther south. Lower control arms bolt right in to the existing holes and so should everything else. You will need a 1/2 ton to 3/4 conversion u-joint for the rear end, since the 3/4 used a bigger u-joint. Front drive shaft will need to be shortened since the 4L80E's where longer, so they could use the length, the 4L60E is not long enough, so you will need to have that drive shaft shortened. I know I am forgetting things, if anyone wants to ask me anything about this project, I will be gladly happy to answer to my best ability!!! :D Oh, before I forget, be sure to lube everything up before installing --> antiseize stuff. If you want, paint every part you take off a 3/4 ton (except front diff., doesn't need it before installing - I highly recommend.
 

98chevy2500SS

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Sorry for the outdated photo, I took that when it was finished. Ever since, I have added chrome tube steps and an over-the-bed black low profile tool box.

If you need more pics, I've got more.
 

98chevy2500SS

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Yeah I do, but they are on my phone right now. Just a sec. :)
 

BowtieBrody

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Sorry for the outdated photo, I took that when it was finished. Ever since, I have added chrome tube steps and an over-the-bed black low profile tool box.

If you need more pics, I've got more.

What rims are those?
Damn I wish my 96 454 was that color, and that it still had a cab-visor; looks sharp as hell!
 

98chevy2500SS

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Thanks man! The rims, I have no clue what brand they are, got them at a swap meet for $100, but had a lot of time in cleaning them. Selling currently to my cousin as they are too wide and they scrape my mud flaps when turning. That's the one drawback I don't like about this conversion, I have to get rid of my favorite rims. :( I measured a true 3/4 vs. my edit and the tires are moved back a little bit on mine vs the true 3/4 (the wheel is more centered in the wheel well, maybe a tad forward, whereas mine isn't, frames are obviously different), so a part of me thinks they did make the 3/4 tons more different than I thought. Trying to look for some GMT800 aluminum rims so desperately! lol

Looked on my phone for pictures of the work and dang it, thought I had some! Sorry guys, I will get some this week of what it looks like now since we had to edit it again. Most likely get them in tomorrow for you guys. :) I will get pictures of: lower control arms, shock re-location, upper control arm mount positions, and front diff mount re-location. Again, I apologize for not having any pictures right now.
 
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98chevy2500SS

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Ok, got pics, sorry that I don't have the front diff relocation mount photographed, I will get that sometime, it's been raining here quite a bit to get under the truck on a wet cement pad lol.

Now, here is the driver's side front mount, we had to cut it and move it upwards, since the 3/4 ton frames are indeed taller:

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Next we have the whole driver's side assembly, got a picture of the best I could:

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Here is the bottom shock relocation mount, since we got 3/4 ton 7200GVW shocks, couldn't find any brand new 8600GVW shocks for it, they mostly have stuff for half-tons. :( But trust me, these shocks are great:

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Here is the passenger side setup, sorta:

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Like I said, the lower control arms bolt right up. No problem there, and to be clear, the keys for the torsion bars are the same, 3/4 ton, half-ton, exact same. We were reading that they were different, but when we placed them side by side, they looked identical. We used the 3/4 ton one's no doubt, since we had to cut the other keys out. Rust, gotta love it.

Now here is how far we moved it up on each side:

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We just put a piece of sheet metal behind the bracket so that it's enclosed. Now, I made mistake earlier saying that you have to move the front mount forward... DON'T!!! That will give you negative camber and you want positive camber. The rear mount is the one you have to move; you will have to move back.

After you have cut the front mount, moved it upward, and welded it all back together, I recommend putting the upper control arm in the front mount, and with the rear mount cut off the frame, put the mount in the control arm link and see where you have to weld. Align it. Try to make sure you measure the front mount how far you moved it, you will want them the same height. I recommend spot welding the rear mount, then remove the upper control arm to finish off welding.

Woof! Lots of typing, lol, if you guys need more pics, just holler and I can get you some as soon as I can! :)

One thing we learned after doing this is that, we will NEVER do this again! lol, just easier to buy a 3/4 ton truck to be honest, but you don't see a 3/4 ton ECSB too often, which I think are pretty cool to see. :D
 
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