Randy,
Welcome to Stovebolt.com.
By "crate engine", you are most likely referring to a GM 350 engine?
Hundreds, if not thousands, of Stovebolters have "enhanced" their 216/235/261 engines.
Try searching on some key words and you will get thousands of "hits"
Here are some upgrades to your generation of 235. Some require significant engine work and others are bolt-ons.
1. Dual exhaust (search on the word Fenton or on dual exhaust)
2. Improved cam - the simplest/cheapest is most likely a cam for a 261 (you should get new lifter with a new cam). Many people go for more modified-lift cams - they are readily available from several vendors.
3. Increased carburetion to match your "new" engine. A larger single carb is easier, but people who like bling go for 2,3,5 carbs (and often do not match those carbs to what the engine can use).
4. Change your head to the common "848" head (1956-1963 casting code 3836848). This is a higher compression head compared to one on the 54 (maybe an increase from 7.5 to 8.25, if you use the right valves/springs/rotators).
Other people will post other ideas.
