Keep it simple. You don't 'need' to change the jetting but if you're chasing every last bit of punch you can squeeze out of the Weber you have to do the research and jet it specifically for what you want it to do. The standard jetting will be more than adequate for a stock engine and will be an instant improvement over the Mikuni. If you want a bare bones install, disconnect the vac lines to the EGR valve, cap off any barbs on the manifold that will pose a vacuum leak once you have your distributor advance line hooked up and bolt the sucker down.