I've likely got a number of factors contributing to the bog and I'll need to troubleshoot each of them. One is a questionable vacuum advance which I'll replace soon. Another may be that it's running too cool. I have no idea what thermostat it has but the temp gauge barely moves up stays low and I've used an infrared thermometer and the intake stays in the 150-175 range. I also disabled the noisy heat riser and the bog seems much worse with it disabled but I'll retry it with it enabled to be sure.

As I continue to tune and mess with timing. How is the best way to modify the distributor to limit advance? Where is the slot that needs to be modified and how is the best way to do so? For each degree that I need to limit the mechanical advance so total doesn't exceed 36 do I need to shorten the slot by 0.015? To find out if my bog is from the secondaries opening too soon would it help to disconnect the linkage and vacuum lines from them and run just on the center carb to find out for sure if it's from those or maybe a faulty accelerator pump or pump setting? I need to check what springs are in the pods but if they are black and the secondaries need to come in even later to stop the bog is there a way to do that?

I'm also still curious as to why offset secondary rods is a bad idea?