how fast about?
 

have a mathews Z7 shooting 65lbs at a 29.5 draw lenth. Have a whisker biscuit, d loop string, peep and arrows are around 420 grains..Thanks

fast enough to kill a deer...

Exactly, isn't that what really matters?

275-285 fps I'm guessing would be very close.

The calculator below show 295 fps and 80.9 ft-lbs KE. Definitely a deer killer.
http://www.backcountrybowhunting.com/articles/tools.php

In my opinion speed only helps with being able to use less sight pins because off flatter arrow flight. If an arrow isn't going faster than sound there is still a chance the deer will jump the string or drop as the go to take off and run. Success is based on shot placement and the ability to read body language. So the answer to your question.........yes, fast enough to kill a deer or anything else for that matter

My Z7 at 61 lbs and a 400 grain arrow is shooting 264-266 fps so that will get you in the ballpark for yours.

Anything other then shooting thru a chrono is just a guess.

ok i used a different arrow speed calculator but i got u around 288-290 depending on the weight on your string with around 79ft/lbs of ke. definitely enough to kill a deer.