Gaines,
2 160 twins??? Wonder if WACO ever thought of building a twin?
Once you get the market cornered on the 160's, you will be Da Man!!
I don't know what prop you are planning to run, but with a Zinger 18 X 6, you should see somewhere in the 8500 plus range once it's broken in. That, Buddy is a ton of thrust. Not too much speed, but when you hit the gas, things happen.
Bill, AMA 4720
WACO Brotherhood #1