hmmmm...you need to figure out what you are going to do before anyone makes too many suggestions i would imagine. Running up hills at glamis....and then turning around and doing mx are two different animals. non-purpose built bikes are tough to build. I'd say ditch the pipes(sell em) ditch the carbs, go get a port job, get some cpi's or rockets, then get some good carbs. SHould be right around your 2g limit. But you'll be haulin ass
oh yeah, ditch the stock head or have it milled. You can usually find used cool head at reasonable price on here or ebay.