SS 640G cam in 127" question on ADV key

[itsafatboy]

So was wondering if there is any bennifit to running a +4 key on a SS640G cam in a 127" 11.3 comp.  or will the ex open be to messed up it would change the numbers to this

29/56  intake   69/21 ex  just not sure on the ex open of 69 , i see some cams with that number but they are the 725 lift type cams ,

the cam in the bike closes at 52 currently but going to change its to noisey, and i am concerned i will loose alot of low end with going to the 640g straite up. maybe not 

[fuzznut5197]

I think Bruce is running an advance key on his 131". A 2.5 degree advance is ground into the cam. Low end? Do you really need 150 lb/ft of torque banging on your bottom end at 2Krpm?