Looking for an enduro / Street and Trail bike that is larger than 400cc. It needs to be streetable but I don't really care about a tired engine. Budget is around $1500
A few things are out of whack here. With your budget, you'll get probably 80's models, and early 90's models bikes. There were very few 400 +cc's made back then, and really arent needed. Why do you want such a big bike? It will likely be too heavy for any trails unless you just want something you can drive on a dirt road. I'd suggest looking for something like an 85 Yamaha XT 350. Even the 250CC Xt had plenty of power.
I'm going to drive on the highway occasionally. Reducing the gearing so that I can do that easily on a 250 - 350 cc does not leave much to say for torque. Late 80's early 90's is all I'm looking for