I was thinking about changing classes from 17.5sc to sc4x4...I just got a gtb3...so with a gtb3 and a 7.4 8000mah 2s 40c-80c and some kinda 550 motor in between 4200-4600....will I be ok with that for racing?
thanks

It will work BUT Novak went under a few months back. So there is ZERO tech support and such. Next question is what 4wd SCT platform are you planning to run? IF you choose a TLR or Tekno, you will have to go with another ESC. Personally, I run 4wd SCT. TLR SCTE 2.0 with Ballistic 550 4.5T mated to a Hobbywing 120A V2.1 ESC.

why would i have to choose another esc for those ?
i was thinking a sc10 4x4.

The TLR and Tekno are HEAVIER than a SC10 4x4. With the heavier trucks in this class, the closer to 1/8 electronics when is comes to an ESC the better.

ok...so does it matter if the motor i get is a 2 pole or 4 pole 550?

Not really. I have done some testing between the 2 and found that for the surface I race on and my needs, a 550 2 pole is less stressful on the ESC and battery after a 6-8 min track session.