The biggest improvement I made to my truck when it had the 235 in it was probably the swap of the original 1bbl Rochester carb with a 2 bbl Holley/Webber carb. I picked up power and torque, and my mileage improved too.
The next biggest improvement was with a change from points to Pertronix electronic ignition. Always started on a dime and ran perfectly. Well worth $70.
