AMerican Racing Wheels 15" wheel info

Man, trying to get info from these guys is like pulling teeth! Maybe one of you guys can help me. For anyone that has 15" American Racing Wheels now, can you tell me what the inner side (car side, ugly side of the wheel) inner wheel diameter is from the rim/lip going up about 2-3 inches inside the rim??????

I need to know this so that I am assured my brake calipers will clear when I order my 4.0 back spacing. I need 13.4 inches in this area for my brake calipers to clear.

Thanks much.

I am running the 15's American Rodmaster w/12 " Willwood Calipers (Billet) on the rear.I do know it's close on mine.I could not put the stick on balance strips to the back ,because they would drag .The front is OK as I am runing 10" calipers.Good luck.