Are all Silver face Champs designed only for 4 ohms speakers?

[Robal]

I recently got a couple of silver face Champ amps from the 1970s and both of them have Fender 8" speakers that measure around 8 ohms. I know that 3.2 or 4 ohms is the spec, but is it possible that Fender changed the OT in later years to handle a 8 ohm speaker? I thought it was odd that both of these amps (obtained from different sellers) would have identical Fender labeled 8" 8 ohm speakers. Or should I just assume that these are replacement/recone speakers with the incorrect rating for the amp? Is there an easy way I can test the OT to determine if it designed to handle 8 Ohm rather than 4 ohm speaker load?

I am just wondering if I have to invest in two new 4 ohm speakers to optimize the amps. If I do need to get 4 ohm speakers, is the consensus that WeberVST alnico or ceramic 8" is the preference? Thanks for your help.

[bob-i]

I've run them with both 4 and 8 ohm speakers. They seem fine with either.

[soulohio]

the Weber speakers are nice...my original oxford farted out when i pegged the volume and i replaced it with a weber...not a huge difference but louder and no farting...