Largest pinion possible with RCM Xray 808 mount?

[SidewaysLS4]

Thanks for the input, I'll definately post something if this idea goes through. I figure a buggy should be really good for speed on any old road with the suspension travel, and since the XRay is getting stellar reviews and seems to be the lightest, it should be really, really good for this project. My current 1:10 speed buggy does a GPS'ed 63 so far, but tire issues slowed down the tinkering to push it more before winter hit. I decided to put some belted 1:8 on-road tires on it to keep the wheel speeds down (still completing the 17mm hex conversion, unsure if the big wheels will tear up the drivetrain). But then I got to thinking...why not go to 1:8 scale, thus this idea, as I need to go above 2S soon anyway, I might as well go 'big' lol.

Youre in Chicago too, eh? I'm a few miles E of Ohare.