
There is not much difference in most carp/barbel rods, however the best barbel rods tend to have more of a through action. This is certainly the case with the Harrison Chimera rods I use on the Trent.
A lot of carp rods are used for distance casting and tend to have a faster taper. You don't want a poker when you have a decent barbel plunging under you rod tip.
Test curves by the way can mean absolutely nothing, especially when the whole concept of the test curve is flawed.
Read Dr. Steve Harrisons comments on test curves in the Harrison Website.