What distriutor do i need?

Are you using the OEM ignition box off the older car too?

I prefer distributors that bypass that, and run as a stand alone...
like these.
READY TO RUN DISTRIBUTOR | MOPAR SB 273-360 | V8 ENGINE | BLACK CAP

or you can buy a really nice "ready to run"
PRO SERIES READY TO RUN DISTRIBUTOR | MOPAR SB 273-360 | V8 ENGINE | BLACK CAP

Or like the post above...you can "rock auto" am OEM one for a 73 ish dart/duster with a 318 if you want to keep the factory type electronic ignition with a OE box.

or I suppose you could even try a cap and rotor first...