2wd to 4wd spring question
 

Just about done collecting all my parts for the swap but would like some help on springs. Up front I found a set of "e" springs which are 5200 lb springs. Should I keep looking for "c" springs? The rear leafs on my truck are code "ff" but I can't find any info. Don't know if they will be OK on 4 inch blocks or if I should replace this as well. Thanks in advance.