I own a 1972 mustang 351 c 2-v V8. Been trying to set the dwell. Have a reading of 44 on the dwell angle. Need to get between 24-29. Got the hold down bolt loose but cannot rotate distributor shaft. Seems to be 40 years of rust holding it. Sprayed with bust rust. No luck. Any tips , tricks or tools I can use to loosen this up ?