can I put JJ's in my Mark IV

I need new tubes badley and dont have the cash for mesa's and Ive heard good things about JJ;s and there 20 bucks cheaper. SO if I put these tubes in the link into my Mark IV would it effecot or mess up the fixed bias.
http://cgi.ebay.com/Matched-Quad-of-JJ-Tesla-6L6GC-Amp-tubes-New-6L6_W0QQitemZ110334950856QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item110334950856&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

You really need to contact the guy (tell him what amp you have) and see if he has a set within Mesa Boogie specs. He has allot of sales with great feedback and seems to deal in nothing but tubes (so that’s a good thing).
Mesa’s have a fixed bias so the tubes must be in a certain range. Run to hot and things will go wrong and a trip to the tech you go, or you just get short life out of the tubes. And if they are running to cold you might not be that all crazy about the sound.

If that guy can’t give you a set in Mesa specs try http://eurotubes.com/ he deals with nothing but JJ’s.
Personally if you can swing it try some SED Winged =C= from Doug http://dougstubes.com/sed.html
Again if you do end up ordering from Bob (Eurotubes) or Doug (Doug’s tubes) Tell them what amp you have in the case of these two guys they would probably ask you anyway.