For the OP,
Like others have stated, if you are just looking to make 50-100 more HP, porting your -1's will be best bet and cheaper in the long run. Your current heads placed in the "right" hands will make the HP range you are looking for. Probably need a cam change too, maybe.
What kills me is all this talk of -13's won't run. I'm sure there are plenty of them on motors running real good; its not fair to say they won't run just because many, many other racers don't frequent this forum to share their story on the performance of their motor w/-13's.
Lets not FORGET, a former Best Machine customer (Lane Lambert) in a somewhat heavy Dart set some All-Motor classes on their ASS with a set of well prepared -13's and 581" Wedge. He did it in competition with a 1.28 60', 8.55 @ 159 in Toronto @ #3310 on a small tire......and it was not a 1-run wonder; car ran fast all the time and won multiple races, 6-yrs ago!!!!!!!! Lane and BMRE went separate ways, but that hotrod was fast!
As far as people stating B1's having valve train issues, this or that......yeah they probably do when placed in the "wrong" hands or people just throwing them together in a hurry......it ain't the heads that have problems......lol.
Haven't made up my mind yet, but I have 572-13's w/Jesel indiv. shaft rockers on my motor currently, but I am seriously considering selling them; they have been CNC'd by Jeff at MCH w/flow data. If I sell I'm going B1-PSO or Predator top-half. Just have not figured out what direction to go yet. IF I make a change, Brian at IMM will get the call for the work.
Wes
