Torque convertor issues with 9/11 stall and valve train destruction.

I like my art carr non lock.
Had two cars with them.

Ypu sure your J rod is synched with your trans. I jave had an issue where cable changed and inn D position was not correct as far as the detent for J rod and cable.
You can remove the j rod as experiment and the valve may be in a better place to allow full flow of fluid

Try it. Could be something as stupid as that?

Of course this is a little dangerous as you can just push lever to park or rev without using the shifter button.
I run an Art Carr 16930. Works mint with this 6262 Precision JB. Build/ET is in my sig.
Back in the day, a converter with your stall speed was recommended for your turbo size so it wouldn't lag. Unfortunately it sounds like you might be "blowing through it" when you turn it up. So much new technology has come out that you'd be surprised what is available now. 9/11's are hit and miss depending on the combo. I picked up 3-4 mph just swapping to a Yank LU with no changes. Tighter on the low end but the top end was night and day. PTC 9.5" NL had similar results.
I would go with a non lock 3200 stall. I don't think you want to go to the other extreme of a converter that's to tight . you will not be able to build boost to launch . I've seen both extremes and have video of each. have you inspected the governor on the trans before you go and re stall your converter?
The 9x11 is good for the street if the stall matches your combo, but does allow a fair amount of slip % unlocked. The billet version can be manually locked at WOT with a switch. Non lockups are more efficient, but you will be turning a couple hundred rpm more on the highway and the trans will have to modified to accept it. Cost of a new NL and the trans mods vs restalling your 9x11 with no trans changes. Just depends what is more important to you.