Hi Greg,

Since the original Shark 45 was flown with the K&B 45, I would think that a resonably built Shark 45 would be just fine with the 46.  It HAS to have more power and less vibration than the old K&B! 

I was told to get rid of the Irvine and get a OS.46
Would you?

Maybe I would because the OS 46LA is so popular and the set ups are out there readily available with many people to help out.  Can't say as to the relative power in a comparison.   My fist inclination is that the Irvine might have the edge there.  I haven't seen the 46LA exhibit the power of a ST G51, which is also readily available, popular in use, and can be had for about the same price as a 46LA. 

I would go with the ST G51 hands down in a Shark 45 if you had the opprotunity to get one.  Even better if its reworked by Randy Smith,  Tom Lay, or Byron.
Those examples have been very strong whe I have used them.  A definite improvement over stock, which is still a very good, strong, stunt engine..

But like I said to start with, the Irvine shuld power the Shark 45.  I have several engines set up by Byron.  All have been very user friendly and performed excellently.

  Didn't know there were options! 

Why not check with Byron?
He was still alive (last time I saw him )and should be able to help you with the set up.
I have always found him to go the extra mile to help.
Give him a call or Email.
My Motto:
Check with the guy that built it; Then do EXactly as his says.