Which option will produce the most thrust, and be efficient? LS3 480 V8 + 96" Prop. Gear ratio 1.9 - 1 This would allow a max cruise engine rpm of 3100. This equates to 195hp (10,000' AGL), and the prop spins at 1630 rpm. Or Gear ratio 2.21 - 1 This allows a max cruise engine rpm of 3600. That's 232hp (10,000' AGL), prop turns at 1630 rpm. In both examples, the tip speed is 465mph, or .60 Mach. Which one will give the best cruise speed in IAS?