by porting we mean making the hole bigger. the hole i am referring to is the 53mmx57mm oval shaped hole that is your throttle body. you take a dremel tool and ream it out. do the same with the intake manifold a little bit. other things you can do to get better throttle response are using lighter replacement parts for the rotating assembly. like the flywheel, pistons, rods, crank pulley, and crank. but since you said you want to improve throttle response by a cheaper method than buying a 65mm throttle body i think all of those are probably out...