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Official NBS V6 to GENIII V8 swap Guide

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Old Apr 6, 2018 | 01:04 PM
  #221  
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Default 4.3 to 5.3 mounting issues

99 sierra, was a 4.3 and 5spd. Now it's a 5.3 and a 4l80. Previous owner custom made an offset mount and bracket. I tried to put factory mounts and brackets (from an 04-06, I think) back in and they won't line up. I know someone has dealt with this before, does anyone have any pointers or advice on what mounts and brackets I actually need for this to line up? Adapters? Different mounts? Keep the custom mount and just send it? (Custom keeps cracking and I have to keep welding it) Custom mount, as you can see its offset a bit
Factory mounts pulled from 03-06 truck, wont line up. Dont know if theyre 2wd or 4wd.
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Old Apr 6, 2018 | 08:45 PM
  #222  
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Originally Posted by Misfits513
99 sierra, was a 4.3 and 5spd. Now it's a 5.3 and a 4l80. Previous owner custom made an offset mount and bracket. I tried to put factory mounts and brackets (from an 04-06, I think) back in and they won't line up. I know someone has dealt with this before, does anyone have any pointers or advice on what mounts and brackets I actually need for this to line up? Adapters? Different mounts? Keep the custom mount and just send it? (Custom keeps cracking and I have to keep welding it)Factory mounts pulled from 03-06 truck, wont line up. Dont know if theyre 2wd or 4wd.[/i]
Why dont you tell us more about what you are working on.

99 sierra, was a 4.3 and 5spd. Now it's a 5.3 and a 4l80. Is not enough info...

2x4 or 4x4
How is the trans mounted in the rear? custom crossmember?
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Old Apr 6, 2018 | 08:51 PM
  #223  
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Originally Posted by 1FastBrick
Why dont you tell us more about what you are working on.

99 sierra, was a 4.3 and 5spd. Now it's a 5.3 and a 4l80. Is not enough info...

2x4 or 4x4
How is the trans mounted in the rear? custom crossmember?
sorry, its 2wd and it's a custom crossmember from a member of this site. Everything else fits just the drivers side mount/bracket won't line up for me. I think i found what i need here, this middle bracket looks like it should work for me.
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Old Apr 6, 2018 | 08:51 PM
  #224  
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This was posted earlier in the thread, maybe it will help.

Top mount is coil spring V6, middle is coil spring V8, bottom is torsion bar V8
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Old Apr 6, 2018 | 08:52 PM
  #225  
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haha, posted at the same time!
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Old Apr 6, 2018 | 08:52 PM
  #226  
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Originally Posted by 1FastBrick
This was posted earlier in the thread, maybe it will help.

Top mount is coil spring V6, middle is coil spring V8, bottom is torsion bar V8
lol posted this pic at the same time. I think this will solve my issue
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Old Apr 6, 2018 | 08:52 PM
  #227  
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Good deal!!!
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Old Apr 6, 2018 | 08:53 PM
  #228  
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I have the 4x4 bracket froma junkyard and didn't know there was a 2wd option.
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Old Apr 6, 2018 | 08:54 PM
  #229  
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Ah... sounds like that's it then
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Old Apr 6, 2018 | 11:53 PM
  #230  
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So the OEM 2wd V6 right (pass) side mount will work with the V8 2wd swap? Can someone confirm the passenger side indeed works before I drop $50 for that new mount?

In my research the V6 2wd (pass) mount has a 15732464 part number whereas the V8 2wd (pass) mount has a 15113847 number. Why two different part numbers if both are the same?

I understand the left (drivers) side must be replaced with part number 15113848 ($67 on e-bay)

I have been looking at these Dirty Dingo mounts that retain the stock V6 motor mounts ($69 shipped). Any opinions on this setup?

2000-2007 4.3 V6 to LS Conversion Mounts Powder Coat DD-V6-LS
https://www.ebay.com/itm/2000-2007-4...75.c100623.m-1

Originally Posted by DirtyDingo
This newly designed adapter plates will allow you to bolt a Gen 3 or Gen 4 LS engine into the place where a 4.3 V6 came factory. 2000 to early 2007 Chevrolet and GMC trucks use different front cross members that are welded in and do not accommodate the LS engine mounts. Will not work with late 2007 or newer V6 mounts. These adapter plates bolt to the LS engine and re-use the factory V6 engine mounts. CNC laser cut from .250 P&O cold roll steel. Grade 8 bolts and washers included. This is a set for left and right engine mounts. You will need to use the factory mount plates. These are GM part numbers 15732463 (Driver's side) and 15732464 (Passenger side).
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