Timbawolf........I got quite different numbers than Ausie

Don' t expect a ton of speed from those specs you listed.........You' ll get more speed than most single cams will at those specs but I don' t think you should expect quite the performance Ausie listed.(his calculator must be on the fritz

)
Here' s what I come up with:
Assuming middle of the advertised speed road on a VFT at 330fps. That' s 30" 70#
AT 27.5" you' ll lose approx. 25fps right off the top for say 305fps.
Next knock another 6-8fps off for a 60# model......down to 298ish.
Now for the biggie.........with a 420 gr. arrow you are 155grs over an IBO legal arrow (265grs at 57#)
If I remember correctly my I-Cam Patriot lost about 1fps for about every additional 2.9grs of arrow weight .........so if you follow that model you can expect approx. another 53 fps speed loss. (155 / 2.9 = 53fps)
That now puts you around
243-245fps range tops....and that assumes no string load.
Still a heck of a respectible KE level of about 56ft lbs at 27.5" and 57# of draw weight!