If you can tell me the RPM it takes to go 30mph with no load and no transmission or rear end, let me know what that number is. Same for 55. Please let me know cause that makes sense. (although now we are talking about TWELVE tests). I feel idle is just slightly too slow for the test because of the erratic behavior of a points distributor at very low rpm. That's why I suggested bumping it up, but not enough to trigger the mechanical or vac advance. I wish you could be here to see what I am talking about when using a high tech timing light.
You asked for RPM equivalent and that's were the numbers I gave you are for.
Load does not matter for your truck to drive 30 MPH it will have to do 1,401 RPM's. For the engine will have turn those RPM's to turn your drivetrain to do that speed.
Load only comes into place in that when load increases the throttle position has to increase to maintain engine RPM to maintain MPH.
Your engine is in a stand and there will be no change in load once you hit target speed.
