Do the "doc dual plane" mod. Make sure you have a good flowing exhaust system. Do a tune up and make sure the timing and carb tuning is dead nuts accurate. Also, you could swap to an electric fan if you haven't already done so. A ram air or cold air setup is helpful as well. Check out the "doc's cheap and easy tricks" sticky too... Obviously, from these simple things, you can get more in depth with things like headers, head work, a cam swap, etc. I've done most of the simple stuff and I can tell you it's make a big difference.
