( FOUND ) 1966 or 67 Mopar Parts catalog

1. Take a 3/4 -10 NC bolt.
2. drill an appropriate sized hole down the center of the threaded section
3. Tap the center to 1/2 -20
4. Cut off about an inch of the threaded section
5. Buy the following or similar https://www.oreillyauto.com/detail/...in-plug/65267/4182329?q=oil+drain+plug&pos=40
6. Put some permanent locktite on the 1/2" thread and screw the reducer you made on.
7. apply pipe dope /teflon tape to the 3/4 threads and screw the plug and reducer into the manifold
8. torque to an air tight seal
9. Go have some fun