Mine has a P-120 and it is way over powered. I never fly it over 2/3 power including takeoff. The prototype was flown with a 12-14 lbs thrust engine according to Nick so a p-70 would be perfect. Watch the main gear mounts; mine pulled out of the wing as they are a litte narrow in mounting plate width.I think that they should go to the front and rear spars (but they don't if built from the plans and kit) in my opinion if you are going to fly off grass. I would glass the inside of the whell well area prior to flight it really stiffens up the skin on the top side of the wing. I also will warn you that it will take off at very low air speed and you will need crow to stick the landing. Mine has 1/4 inch up on the ailerons with full flaps and about an 1/8 inch of down on the elevator to set the glide slope. All in all a great flier and too bad guys don't want to build anymore, that is why you don't see many of them. I get offers to sell mine at ever rally I fly it at.