I have found a Upper control arm that works with ARC.
https://cognitomotorsports.com/cognito-ball-joint-sm-series-upper-control-arm-kit-for-19-20-silverado/sierra-1500-including-at4-trail-boss-models.html#mageworx_product_attachments
I contacted them directly on this issue and they said this will work and it actually does have the attachment point on the side for it!
I have a slight tick as well I'm not even to 20k yet on my 18... I was told it was injector tick but its not consistent enough in my opinion to be that. As in one day its there and the next its gone... then a few days later its back...
I really want the L86 motor in my truck but i'm currently stuck with the L83. Has anyone done a successful swap of these 2 motors? I'm curious what all would need to be modified or changed out as well. other than the obvious ECM/PCM. but Would the 6 speed be useable or would I need to swap out for a 10 speed?