Full flow oil filter. Go to the tech tips for instructions. M4F cam. Cast iron headers or get your's split at Kansas Kustoms. Carbs, go with duals, either ones or progressive twos. Electronic ignition of some sort. Hardened exhaust valve seats. Umbrella style valve seals. Find a 848 head, higher compression. If you really want to add more oomph, get the head ported and shaved, and balance the crank and rods.
If that isn't enough, get a 261, put in a full race cam and the dual progressive two carbs. With the mods listed, you will have a 200+ hp engine that is very streetable, and will rev to 5,500 rpm.
