your carb has a low and high end needle adjustment from what I can tell the high is where whe fuel line hooks to the carb and the low looks to be where the rotaty arm is in the middle of it.Your idle screw is right below the air filter.
Cool thinks I bought my first GT back in 1995 and sold it bought my last one in 2000 sold it later on when I got into the MT scene. I loved the trucks just not quite big enough for what I wanted.
http://www.ebay.com/itm/Associated-RC10-GT2-Interceptor-Lexan-Truck-Body-/231617114489?pt=LH_DefaultDomain_0&hash=item35ed74b179
Any 1/10 scale stadium truck body should fit I believe.
Looks like an RC10GT to me not sure bout the black tub though. I had 2 of them at different stages and I can't remember the color of the tub on the first one the last one I had was blue though.
Another black one on Ebay...