Couple of questions I m hoping I can get answered here. I’m looking to put a 54/23 gear combination in my 5b. Would I be correct in saying I need #19 engine inserts? Figured the 5t stock gearing is 58/19 with a #19 inserts. 58+19=77 & 54+23=77 so I’m concluding I need #19, right? Also what are these 19.5 and 18.5 inserts for?Hopefully someone here can straighten me out here.