Small block, 327, Edelbrock 500, but otherwise stock. This winter I’m going to convert it to an electronic ignition to hopefully improve the gas mileage. It’s a blast to drive, it’ll pass just about anything but a gas station.
Lotta iron to haul with a stock SBC. An HEI out of a later model ( mid to late 70’s early 80’s) will make a big difference and be pretty simple to wire up. Headers can get you 10% or better, too.
A torque cam (1500-4500 rpm) will still idle smooth but pull you around nicely, depending on your gear ratio.
You can keep that babe going forever pretty cheap but you might want a bigger carb - 600- 650 Holley and a Performer manifold. Your mileage then will depend on your foot but you’ll have lots more bang with the same or better gas mileage.
You can do all that for 5-600$ if you shop.