Bob Smiley wrote:

Yes, Flowing the heads, 10.5 to one pistons...


Here are two more data points:

1.  The folks at Performance Engines, in Corona, CA told me that those changes, minus the propellor should give a FI 180 HP Lyc IO 360 about a 20 HP boost.

2.  I was taught a rough approximation of speed gain for HP gain (EVERYTHING else held constant) is

V2 = V1 *  cube root ( 1 + delta HP/ HP)

Where V2 = 191.6, V1 = 185, delta HP = 20, and HP = 180

Experts - please correct the formula if wrong.  Taken together though Bob's results make sense.  A 20 HP gain would take him from 185 on up to ~191 KTAS.

Bob,

What were the conditions (temp, alt, baro press, etc) and power setting for those three speeds, 185, 191, and 202 KTAS?  Was this WOT, how were you leaned?

Thanks,

Tom