Need a plan - component selection for restoring 68 340 that runs on 91 oct

With the limits of the X heads I figured make them work at a broader rpm range with some more CU in
Depends on how OP wants to drive
If hes back roads and curves and mountains then a high winding build would be fun
around town or even urban freeway the more torque the better
just step down on the gas and go with less shifting down
his call- and it's an important one
what you are not going to get with today's gas is the sharp, crisp bark of a big cam high compression motor- It's never going to sound like a 327 vett (sob)
bye the way Stock Manifolds? Stock intake and Carb- which carb? Do you have the larger 68 340 4bbl stick only cam in it now?
would you consider a Solid cam?
for your stock rods the SPS (Mopar performance) bolts work just fine
here is the piston for a 4" stroke
KB Hyper Piston - Chry 408 Rod 6.123 Quench Head 23.5cc 2V [KB356KTM] - $518.30 : United Engine & Machine Co. Incorporated, Performance Pistons
even if you do not go away from stock stroke you can see the design required for an efficient combustion created with the stock heads