http://www.jcmotors.com/progressive-suspension-412-series-13-chrome-rear-shoc...It appears that the 4218 shocks are 13". That is a bit tall for the bike unless you are doing a Cafe' Racer. One other thing to pay attention to is the standard or Heavy Duty spring rating. The Heavy Duty might be a bit stiff for the Savage....when you read the Progressive webpage they state the Heavy Duty springs are for Double Up riding, and probably they are talking about double up riding on 600+ pound bikes.
When you are buying used shocks you need to find out the shock length and the spring rate.....not everyone lists that.
The stock shocks are 10.5". Something 11" to 12" is best for the stock cruiser look. Taller than 12" and the back fender is way up in the air.