Sounds like you want some mileage to go with that setup. I would get a 74 to 75 distributor core with the 15R governor in it. That way you have some room to dial it in for performance and mileage.
For example here is my set up.
New 1974 electronic Distributor re-curved with a red primary spring and extra long looped secondary spring from a 400 big block distributor. 340 distributors are good to rob springs from too. Using a 15R governor with a 11R V8 vacuum advance screwed in 4 turns, (VC-208 11R can $10.26 at www.rockauto.com). Blue Streak cap, MO-3000 Echlin rotor, Chrome Blaster 2 coil, MSD Blaster .85 ohm resistor instead of the stock MOPAR resistor, Orange ECU and 8mm Blue Summit wires, NGK UR4/6630 plugs gapped at .040. Timing set at 16 degrees initial, 16 degrees mechanical and 20 degrees with the vacuum advance for a 52 degree total at 2500 rpm.
For cruise at 50 mph I am 2000 rpm, at 60 mph I am 2500 rpm. On the freeway I am between 65 and 70 mph.
Tuning: Adjustable vacuum advances can be adjusted to when the advance starts, not the amount. The part# number on the can or number on the arm indicates the total amount of advance x 2.
Using a 3/32 allen wrench you can adjust the advance to where you can plug it in and unplug the vacuum line and see zero or little timing change. For me that is about 3 - 4 turns.
For reference, at idle with my cam I am at 18 inches vacuum. So there is no advance from 18 inches or less. Then you have it set right on. You don't want the vacuum advance to kick in too soon or it could over advance and surge or when the engine is too hot, causing it to ping. At cruise I run between 15 and 22 inches of vacuum. At 15 inches vacuum and 2000 rpm puts me right at 30 degrees timing, 19 inches at 2500 rpms puts me about 45 degrees. Letting off slightly say 20 inches takes it on up to 52 degrees.
The MSD Blaster coil swap provides 10 volts to the coil for good spark.
With the little one barrel it will light up the P235 tires at the slightest aggressive pressure on the gas pedal. That is with a 2.76 gears in a 8 3/4 posi-traction rear end. With a four barrel you would be in good shape for a long burn out.
