this amp has a charming sound to itAssuming of course you like warm vintage cleans, and angry chainsaw distortion!
Good description.

I don't think running it into overdrive would hurt the transistors, as long as heat doesn't get out of hand. I don't know of any Peavey amps that can't do 4 ohms if not lower. Double check to be sure, but it could be just that it's an 8ohm combo with no extension jack. If you don't want to do the headcase thing, could just add a parallel jack on the back of the combo. My speaker seemed to handle a lot of that distortion, but, I think I'd be more concerned about cooking the speaker before the amp. With 2 of those speakers, they could probably handle running the amp all the way up.
In other words, with 1 speaker, I'd think the speaker would be the weak link. With 2 speakers, then I'd be watching the amp heat.