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4L80E swap

SpeedlabDan

SpeedlabDan

Keepin it trashy never classy
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There may be a thread in here somewhere but I wanted to see if anyone has any experience with advanced adapters 50-0410 4L80E adapter and input shaft conversion. It's said that the cross member does not have to be moved retaining current drivelines. Im currently running 383ci stroker so my th350 is on the way out and I'd love to have od with my 4.88 gears. Thanks in advance
 
th350 length is shorter than 4l80-e trans .

there directions right on there sight say this WILL REQUIRE drive line modification in red letters . and the transfer case will need to be machined for the bigger input bearing size and full diss assemble of the case will be required.

for your use mabye a good built 700r4 would be better . still longer than th350 but not as long as 4l80-e .

also 4l80-e needs standalone computer to run or full man conversion and always shift it like a man trans minus clutch .
 
sweetk30 said:
th350 length is shorter than 4l80-e trans .

there directions right on there sight say this WILL REQUIRE drive line modification in red letters . and the transfer case will need to be machined for the bigger input bearing size and full diss assemble of the case will be required.

for your use mabye a good built 700r4 would be better . still longer than th350 but not as long as 4l80-e .

also 4l80-e needs standalone computer to run or full man conversion and always shift it like a man trans minus clutch .
Click to expand...

Thanks for getting back to me @sweetk30

Yes I understand that the 4l80 is longer but they call for the use of a 2wd slip yoke trans. The input shaft is changed in the tcase which kinda sux as I've just rebuilt my 205. I did reach out t them to clarify. They only state the overall length with adapter to be 30". I guess when I get home I could measure it myself.

As for the tcm, I have found some options for stand alone and also a company called Jakes performance offers a relatively inexpensive option for a manual controller similar to my current manual valve body.

I'd love to run a 700r4 but after running this engine setup in a 86 K5 it ate up every professional built 700 we put in it. I guess I'm grasping for straws here in hopes not to change the tcase location on such a short wheelbase
 
sweetk30 said:
th350 case length 21.5" long no adaptor .

4l80-e case length 26.5" long no adaptor .
Click to expand...

Ok so I just went out to measure my th350 with adapter is approximately 25" so if their total measurements of 30" are true I'll have to move the cross members back and shorten my brand new high angle double cardan shaft...
 
Did you ever figure this out? I have mine mounted in the stock position and it looks good to go on the engine moved forward with electric fans.
 
SpeedlabDan said:
There may be a thread in here somewhere but I wanted to see if anyone has any experience with advanced adapters 50-0410 4L80E adapter and input shaft conversion. It's said that the cross member does not have to be moved retaining current drivelines. Im currently running 383ci stroker so my th350 is on the way out and I'd love to have od with my 4.88 gears. Thanks in advance
Click to expand...
Hey, I know this was a few years back. Wondering if you were able to complete the conversion? I am in the process of almost exactly the same process. I am really new to this process but have found some folks that have been amazing to work with. I have a 383 stroker that should be coming in a few weeks. I have just ordered a 4L80E that will be fitted to a NP205. I found this tread as I am starting to research the crossmember and mount application as it does seem this transmission mount is almost 5" back from the TH350 location. If you have, or if anyone else here has completed this, would love to steel a few minutes on the phone getting your experience. Thanks Steve
 
Youre asking the wrong guy as this is my first rodeo. I’m going from a th350//np208 to a 4l80e//np208. I’ve got the new input shaft for the t-case. Still need to figure out the crossmember. My brand new rear driveshaft is gonna have to get shortened as well as my front driveshaft lengthened. Probably force me to cut the leaf spring pads off and get those reset at a decent angle also considering how much shorter I’ll be making the rear driveshaft. Made myself tired thinking about all of that.
 
SMK5 said:
Hey, I know this was a few years back. Wondering if you were able to complete the conversion? I am in the process of almost exactly the same process. I am really new to this process but have found some folks that have been amazing to work with. I have a 383 stroker that should be coming in a few weeks. I have just ordered a 4L80E that will be fitted to a NP205. I found this tread as I am starting to research the crossmember and mount application as it does seem this transmission mount is almost 5" back from the TH350 location. If you have, or if anyone else here has completed this, would love to steel a few minutes on the phone getting your experience. Thanks Steve
Click to expand...
Crossmember depends on which adapter you use between the 4l80e and np205.
 
SMK5 said:
Hey, I know this was a few years back. Wondering if you were able to complete the conversion? I am in the process of almost exactly the same process. I am really new to this process but have found some folks that have been amazing to work with. I have a 383 stroker that should be coming in a few weeks. I have just ordered a 4L80E that will be fitted to a NP205. I found this tread as I am starting to research the crossmember and mount application as it does seem this transmission mount is almost 5" back from the TH350 location. If you have, or if anyone else here has completed this, would love to steel a few minutes on the phone getting your experience. Thanks Steve
Click to expand...
No I'm still runnin my th350
 
Thank you guys. My brain hurts often trying to learn all this stuff. Am enjoying.

Have you found a crossmember that works.
 
hello all, I know It is a little late but i've been watching this forum for over 3 years with not much movement. However, if yall are still out there I have successfully completed the 4l80/205 swap in my 79 K5 over these past couple months. I am currently running it behind my holley sniper controlled vortec 350 and I am using their transmission controller to do the work for the transmission as well. I have been running it for about a month now in north Texas, running cool in town, around 130-140F, and 150-160F on the hwy about 80 mph. I used the advanced adapters kit from summit p/n:50-0410. you will need a 2wd transmission unless you plan on pulling apart the transmission to add a tone ring, this is one of the first things installed in the trans it that gives you an idea. I also ended up needing to cut the tailshaft on the trans in order to mate the t-case flush. As far as the crossmember goes I moved It back a couple inches and welded tabs where the overhang was slim (picture below)
IMG_5923.jpegIMG_5924.jpeg

Next thing was the drive shaft, in my case going from a 700r4/203 combo to the 4l80/205 combo the only thing that changed was the rear drive shaft. I did end up getting a new one made so consider it in your budget.
any other questions just let me know
 
To lessen extra transmission length... Balance the difference between the engine placement and the transmission cross member placement...
 
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