I believe those shocks are 95mm so springs maybe like 80mm? not exactly sure, but you could also try to change out the stock shock oil and I'm guessing that the stock shock oil is 20wt or maybe 25wt shock oil? So, I would put some 35wt, 40wt, or maybe even 45wt oil in them and should help. Are you using the truck just for bashing? or racing with it?