STROKE IT! It's not as expensive as you think. 68 cubic inches is nothing to sneeze at.
Build a stroker shortblock and drop the stock (freshened) heads back on. Re-use the 383 cam if money is tight. You'll love the 500 foot pounds of torque more than the 375-400 horsepower.
The 65 383, unless its a HP version, has very low compression also. They used dish pistons and the actual CR is around 8.4:1 (actually measured on my 65 383).
The mopar heads love home gasket matching and bowl work. Just don't get carried away.