Man, I used to get his sound from a King Biscuit Flower Hour
concert off the radio in 1982.
If you can, get a rectified type tone, split it one dry and wet or use effect mix, blend in a slightly off pitch sound by using a pitch transposer or harmonizer if you have the capability in the Guitar Port, and mix it with the dry sound and voila!!
I use a J-station and can nail just as I did in the 80's.
It can be done with a chorus as well. Splitting and mixing one dry and one wet is the key to get that huge sound.
Use a beefy rectified sound with high output pickups and you should get real close. Dimarzio Super Distortion or Duncan Distortion.
Peace and Good Luck, ET [img]images/smilies/rock.gif[/img]