Hi 66M2012,
Our little sixes respond to the same power mods as any V-8.
For performance remember the 3Cs of Power: Camshaft, Carb and Compression.
The other mods that seem to have a good effect are headers (along with larger exhaust system), going to an electronic distributor (versus the vacuum only Load-o-matic, especially if you swap carbs), and a deeper rear gear.
Each subject above has a few options, but please do a search and then ask more direct questions.
tanx,
Mugsy 8)