+1 on the HEI! It's a pretty easy conversion, assuming the dimensions of the mounting are similar to the 235/261 engines. I machined a HEI distributor for an exact fit to a 261 recently, including a custom-made hold down bracket, and that approach works a lot better than trying to adapt the wobbly bracket from the rotating-housing original distributor with the vacuum advance. Be sure you use a big enough wire from the ignition switch to the dizzy, without any resistors in the circuit.
Jerry