Kinda long. I'm currently putting a 4l80e into my 2003 half ton chevy. The engine is a 427 LSX and the trans is out of a 1998 3/4 ton chevy. I am having the trans converted to 4wd at a local shop. I am wondering what harnesses I'm going to need to get the wiring to work and who I should talk to about getting a custom converter made. I need a custom converter because i am using a TCI flexplate made for use with the 4L60e.

 

you just need a conversion harness, speed enginering or speartech. I'd ditch the tci and not try to find a custom converter...

 

4l60e flex plates are setup for 3 torque converter bolts as the 4l80e flex plate is setup for 6 torque converter bolts. Yank makes 4l80e torque converter for the 4l60e flex plate (3 torque converter bolts), which is also nice cause no spacer is needed on the flex plate.

 

The Stock TC is fairly loose for a Stocker.. I went with it cause i didnt want to pay out the Wazoo for a stall that wasnt rated to tow..

Well what do ya know....

You dont need the Harness... Just swap the Brown and White wires on the TRans connector.
Get a Connector for the Front VSS and run it to the PCM.. Done!

https://www.performancetrucks.net/fo...d.php?t=413157

 

So if you use the ls1 flexplate on the 6.0 with no spacer what does that do to your starter ring gear alignment? and if i use the 6.0 flexplate with a spacer on my ls1 with my 4l80e what does that do to my starter ring gear alignment? are the starters different? or are the bolt locations in the block different? I beleive the 6.0 flexplate is straight with the mounting locations raised, where the ls1 is concave so the starter ring gear location is the same?
I also noticed the flexplate bolts for the 6.0 have a little collar,or sleave around them on the unthreaded shoulder, Does this come with the bolts, or is it part of the flexplate??

 

Well, I found the answer, I laid both flex plates on the table, the ring gears line up the same, the 6.0 is straight with the mounting area for the converter pads slightly raised. with the spacer next to the crank. the center is out further giving more support to the snout of the converter. The ls1 flex plate is concave, with no spacer, so the converter snout would not have enough support in the pilot of the crank. I'm going with the 6.0 and no shims, it also takes different bolts 12563533 for the flex plate. they are longer and have a ferrel on them.