(non pedal)speakers impedance and wattage

[frankie5fingers]

Yeah, that was it.but apprently from what I understand a valve amp doesn't work as a solidstate amp in matter of power dividing from 4 to 8 ohms.So, anyway my conclusion was to just get a speaker rated 100watts, and problem solved

I just reread your post garfo.  You're not asking if it's OK to mismatch the head and speaker are you?  Am I correct that you want to know if the amp, rated at 55 watts at 4 Ohms is within the 35 watt range of the speaker if you run it at 8 Ohms?
If that's the question the answer will really depend on the amp and the speaker.  Many (most) guitar amps use an OT with at least two taps for a couple of speaker choices.  Some are 4 and 8 Ohms, some 4, 8, & 16.  A few have only one, like some old Fenders with a 4 Ohm tap only.  Anyway, that's guitar amps.  There are also some solid state types that allow for bridged (mono only) use of the 16 into 8 or the 8 into a 4 Ohm load.  Assuming you have a normal guitar amp, using a different impedance load won't result in a lowered wattage (by much anyway), your 55 watt head is going to be 55 watts, whichever OT tap you use to match your speaker.  The speaker, if rated at 35 watts may or may not be rated higher for a "peak" power spike.  In all likelihood though, if you see it's rated 35 watts, you don't want to exceed it often, or by much.  Without more info, that's all I have.

Great.  100 watts may be a little overkill but it's the right way to go.  Sorry I didn't get your question at first but you got the solution and that's what counts.