It depends on how the 4x10 cab is wired. If you are doing the wiring yourself, you want to wire it (the cab) with each pair of two speakers in series, then wire the pairs in parallel. If the speakers are each 8 ohm, that will give you the 8 ohm output you are looking for.
Here is a link that you can check out for many different speaker wirings (including the series-parallel I describe above):
http://www.soundcitysite.com/sc_webpages/wire_diags.htm
I hope this helps.
"...and I am outta here!"
Scott
Guitars:
Dean EVO Exotic Burl, EVO Special, Vendetta 1000 FR, Stagg Les Paul copy, Squier Standard Telecaster, Squier MIK Stratocaster
Amps:
Fender Princeton 65 (solid state), Vox AD15VT, Peavey Windsor Studio, Crate Vintage Club 50 2x12
Pedals:
DOD FX40B (x2), FX50, FX52, FX55, FX65, FX67, FX80
Washburn LSESLD, LSBOD
BBE Free Fuzz
Behringer EM300, VP1, PH9
Dunlop GCB-95
ProCo Rat II "The Rat"
DigiTech Bad Monkey, RP90
Rockman Soloist
and many, many, many more!