That sounds like an excellent plan for a fun street cruiser with good economy. With properly prepped 302 heads and an RV cam you should be able to run six to ten degrees of static ignition advance (vacuum gauge set to find sweet spot and limit mechanical advance for 30-32 degrees all the way in at cruise rpm in high gear. Limit vacuum advance to around 16- 19 degrees, 302’s tend to work well with 46-49 total at cruise, depending on cruise rpm. My personal experience fine tuning a friends very porky ramcharger with a well worn 87 B-250 van 318 with stock roller cam, 302 heads, eddy performer 318/360 intake and a Q-Jet ran best at 7 static, 30 degrees total all in at 2200 rpm on a constant diet of 87 octane junk gas. Admittedly, it wouldn’t have gotten by with that if it wasn’t down on compression. It was a bare budget leftover parts build and the engine had 147,000 well maintained miles on it when it came out of said 15 passenger wagon van.