I hope the OS.77 you have has an aftermarket connecting rod in it. The .77 had a problem with the stock rod. It won't live very long in a Dynamax. The K&B1.00 does not have that great of a reputation in the Dynamax either. It works well in a Byron or Ramtec where the RPMs are lower. The .77 will work well, if it has an upgraded rod in it. RPM was the manufacturer of the rod, but I don't think they're in business anymore. I would try to find a deal on a OS.91 if I could afford it. You won't regret it.

Make your inlet as smooth and large as possible. I Think on the Yellow Aircraft A-4 the nose wheel opening is used as a cheater inlet as William mentioned earlier. Some kit manufacturers used to recommend spring loaded "blow-in" doors on the cheater hole. Miller recommended 2 of them on his T-38 kit, just ahead of the Byron fan unit. I built it without any cheaters and decided if I determined I needed them, I could cut them out later. The plane got off the ground in about 150' without them. If you've got plenty of runway, try yours without a cheater. You can always go back and re-engineer.

One more word of advice: Seek advice from experienced ducted fan pilots. Sometimes it's hard to tell the difference between the person that has jet experience and the person that thinks he knows all about it.