I currently have a mechanical advance dist in my blown BBF. I had it recurved at a local shop. At the time I didn't have a MAP sensor. I know have the abilty to retard timing as I'm making boost. Which leads me to the question; am I better off not having any advance in the distributor ? Does it make any difference at all ? Should I just remove it and install another that's locked out ? My box allows me to dial up timing retard during starting and while under boost.