Tower Hobby sells a Master Air Screw 550 with a gear box and prop for around $36.00. I have used this with a 2M Aspire with good results on 8 cells. Here is the part number LXZ903. It is a cheap set up.

But I would never advise anyone to put money into brushed motors with gear boxes.

Flying to me is all about air time. And brush less will get you more air time. Brush less motors are an investment you will not regret. But if you want to go brushed look at the Master Air Screw units.

bob