Does anyone make fittings or adapters that will screw into the later 2007 up 4l60e cases? That allow the older screw in flared fitting lines to screw into them? I have customer who did and LS swap and needed a Late 4L60E but also has new older style flared fittng lines he wants to use with it, So looking for an adapter or fittings for this. Not seen online yet. But could swear my 95 ss did have the larger thread set up like that but may have just been on the flare side as it does have the larger lines factory .

 

What's the thread size on an '07-up case?

 

I am not real clear on that , this is the 2007 up fitting https://a.co/d/bmoy07L

This is the earlier fitting https://a.co/d/hj0smse

But what he wants to use is this type but with correct threads for the late 60 case https://ebay.us/m/fVB2VI

I am not sure such an animal is made .

 

case side is 9/16-18
Hard lines are typically 5/16 inverted flare
I don't know of any off the shelf options

Best option would be to re-tap the case for 1/4 NPT
The NPT will be loose to start but as the taper grows it will eventually start cutting the case.

Then you can just run a standard 1/4NPT to 5/16 inverted flare

Your other option would be to get a "6ORB to 1/4 NPT Female" which is 9/16-18 thread on the ORB side (o-ring boss) and then of course 1/4NPT female to use to adapt to your inverted flare.

Another option would be to cut off the inverted flare and add a nut and ferrule and re-flare the line to 37 degree JIC and then just use a normal JIC aka AN fitting adapter in the case