I've been checking around for the motor range and can't find it.
If you are asking about the size of engine for the Pinto, I guess I did not directly answer your question.
The Pinto is small. It can fly the entire pattern. To fly at its potential, the weight needs to be kept to around 11 oz. A Cox TD .049 has more than enough power for that airplane. You should probably not use an engine that is any heavier. In fact, a better match would be a Cox Medalian .049. A Brodak .049 would probably be adequate, though I think you would be better off with either of the Cox .049's. A Norvell Big Mig .049 would also be more than enough power. A Norvell Big Mig .061 could be used with little weight penalty, but I think that would be almost too much for that small airplane. The Novells are fully capable of doing very well in a stunt design of up to 240 -250 sq. in. but the weight still needs to be kept to around 12 oz.
If you insist on using that .070 or anything in that size, there are few, if any "stunt" designs available to match that. Bob Baron's Barecat was flown with the Cox TD, 40 in. span, 356 sq. in, 14 oz was competitive against Open competition when Baron flew it. It could be flown with a bigger engine, but weight is still a factor. This one is sort of "outside of the box" of conventional wisdom but it works.
Keith