This is the exact setup we're using this year and the output shaft fits fine on the AM KOP frame. We should have a video of it up and running here in the next day or two. Feel free to PM me with any of your questions.
Here's an image of it while it's still being built but the gearboxes are attached. You'll see a lot of shaft that we actually need to chop off.
Note: Don't use WD-40 to lubricate your gearboxes, that can was just sitting there for some reason.
The great thing about the WCP SS gearboxes is you have four options for pinion gears, so if you feel like you're going a little too slow or a little too fast, you can easily change pinion gears to adjust your top speed.