Ok update: the quads hubs won't work, bolt pattern qis way to far apart, and they don't have anywhere to redrill new holes so ya.
Going to be ordering a pair of these:
https://www.bmikarts.com/mobile/product.asp?itemid=2907. Since they're 4 on 110mm spread like one set of my rims.
Also going to be ordering a set of these for the back:
http://www.mfgsupply.com/53-681.html
And these rims for the back tires:
http://recstuff.com/8X7-4-4-White-Bell-Trailer-Wheel.aspx
Also getting a custom length axle @ 1" for the back from bmi, gonna be 30" with 1.5" threaded ends which should be plenty of room to accommodate 2 tires side by side, 40 series sprocket and hub, disc brake and hub, and all the locking collars.
Getting a set of 3 hole axle hangers from bmi too.
The jackshaft I have came from a snowmobile and is hex bore, and I toyed around with the idea of having it shaved down to 3/4" round, but then found a nice hex bore hub with weld on sprocket that will fit it in 40 pitch for cheap enough so may go with that.
Getting my frame all welded together, which I'll post up some pics probably next weekend after I get some more finished. ..
It's slow going right now, but I'm getting there. Just hoping to have it finished by the deadline right now as the main constraint is $ lol, but I'll get it done. Really hoping the engine doesn't give me problems, but I guess I'll see.
If anyone has any suggestions on anything it would be greatly appreciated.
O, and I also won't be doing brakes on the front like I had hoped because I'm switching hubs, but that'll be ok as I'll just go with something beefier on back.