Shorten the slots so you get 34 total. You could send to a shop or have one built or YouTube how to make it happen. I found a 383 in typical ky weather during the summer on 93 octane ran choppy on 38 total, little better on 36, and smooth as silk on 34. The 38 total got about 1/2 a mpg better, but felt all wrong. I think it pinged and it couldn’t be heard, got lots of popping in the exhaust on decel. Just not happy. Kept backing down and running same loop until it felt free and fast. I didn’t track that car so no idea what those changes netted out, but it had more zip with less timing. I think the strap is showing it firing way down the side and not at the tip.

You run clay city?