I can't find specs for either of those servos. Maybe I'm blind but you'll have to hope someone else chimes in since I'm familiar with neither.
What's the deal you're looking at online? Maybe it would be a good idea to buy the package for the other electronics and then sell those servos and buy a specific one.
There are a lot of good servo suggestions in the Official SCTE thread on the Off Road Electric forum. I know the Hitec HS-985MG, Spektrum S6040 and Savoc 1268 are all popular choices for that truck.
Star