There is always debate on that it seems. I will keep the 108 in that case. It does get a bit confusing at times thou because pipemax does call for a 112-113 lobe sep in my combo. I have been told heavy cars need narrow lobe seps. To me, it would seem best to pick lobe sep in accordance to convertor stall and duration to rpm between convertor stall and max shift point. Always a learning curve.