Bridgeport Torq-cut transmission speed?

Hi folks, I have a Torq-Cut 22 and will be getting a spindle rebuilt. I am looking at options for boosting my spindle speed limit through upgraded bearings.

My question is, what would be the limit for the transmission?

I have already reduced the driven pulley size but it's not enough. The motor can do 8k but the VFD was limited to 6.1k to set the spindle top speed to 7.5k.(btw, the manual says it's a 1:1 trans.... all lies. The trans is something like 0.93:1 in high gear)

I know the tc3's have the same trans and had an option for 10k spindles. How did they accomplish that? Bigger reduction in the pulley ratio or running the motor faster? Maybe both?

If there's anyone with a TC3 10k that could tell me what the VFD max speed is set to it would be massively helpful to me.