There is a limit to what you can get out of a 235 ci. The heads seem to be the limiting factor. There are still parts available such as twin carb manifolds and headers. Look at
http://www.stoveboltengineco.com/ and
http://www.cliffordperformance.net/they have performance parts for these engines. The performance will not come cheap. After looking into this, I have decided to run the truck stock for now and will reevaluate after putting some miles on it.
