5% od sc + 5% od js = 10% od sc?

if blowing head gaskets is a concern, I'm just curious why some members do the 5% OD SC pulley + the 5% OD JS pulley when they could just do a 10% OD SC pulley...there must be a reason & I don't know what it is...if someone could shed some light, it would be appreciated

yes it the same. Overdriving from the JackShaft prevents belt slipping on the pulley.

The SC pulley will continue to get smaller if you want more OD so less area for the belt to grab the pulley so you get a higher chance of belt slip.

agreed. i have a 10% on the sc. i have no slip but if i was to do it again i would get all 10 on the js or split 5 and 5. plus with a 5% on the sc you dont have to get a different belt. im not sure about for the js. either way its easier on your belts to split it up if you can.

thx for the info