It seems I jumped timing during some "spirited driving"--an interesting event for problem solving skills.
What timing chain set and balancer are best for a mild street 390? It seems there are some variations based on who manufacted the cam (for the timing set--dowel placement). I don't want to order the wrong part, but don't have it apart yet. Based on documentation from previous owner, this engine has a Bullet cam in it (though this is a paperwork-based assumption).
I searched previous posts, but tech does change....