Red, If you are scratch building a chassis/frame, you can build to whatever engine and horsepower you desire. In that case, the body just becomes a weather shelter!!!

What you can't do is to expect an 80 year Ford OEM Model A chassis/frame to be compatible with mega horsepower no matter how much you box and reinforce. Many, if not most a re tweaked either from collision or the crummy roads of the late '20s and '30s. The transmission cross member and often the front cross member is cracked and to the point that they are unsaveable. A TCI perimeter frame is a good place to start and not really expensive - as long as you don't get carried away and buy all of their chrome and stainless (which I have on mine

Don't forget - we are here to bounce ideas and questions off - and most folks have a lot more experience then me.