No need to wait for the rebuild, you can pull the carbs & add the VF3's no prob, If you only ride sand then it's a good idea to remove the whole airbox and go with bolt on filters. For sure advance the timing to +4, and you don't necessarily need a cool head, for about $20 you can have the stock head milled and move up on compression. Wan't a quicker rev? Get that flywheel lightened as well for the same price! I got a guy who does portwork for less than all your bolt ons put together.. He got my shee to do 4th & 5th gear wheelies at the drags. PM me if interested.