how much lift will 3" lift shocks work for

IDK depends on what brand of shocks, most 3" lift shocks are made for 0-3 inches so the may already be close to being maxed out.

What are the actual shock dimensions?

not sure of the dimensions. but they are rough country 3"

i'm gonna go out on a limb here, and guess shocks made specifically for a RC 3" lift, are gonna work for a lift height of somewhere around 3 inches.

According to the link below, front stock length shocks work well with a two inch lift. I would infer then, that shocks in frontg optimized for 3 inches of lift would be OK with 4 inches of lift. If your shocks in back are too short, I wouldn't think you would have to worry about shock damage, they are certainly not going to overcompress. At worst, you just have shocks in back that will droop about 1 inch less than shocks tailored for a 4 inch lift. If you get longer shocks you may have to adjust bumpstops again (assuming you did so when you put your 3 inch lift on).

http://members.aol.com/Stvns/XJhelp2.html

thats why i asked because i had a budget 2 inch lift on an old xj and used the stock shocks so kinda thought it might be the same with longer that they could go alittle higher

idk because i'm running a 4.5" lift with 3" skyjacker shocks and they're fine. doesn't flex as well but i'm not too concerned with that

I used my stock shocks at 3" for a while up front (2-3 yrs)