2" Headers are going to hurt HP on the dyno - we have seen more than 30+ HP loss with the smaller headers going from a 2 1/4" to a 2" to 2 1/8" stepped TTI header - I can also tell you from experience those heads did not work well for us with that cam spec on the exhaust side. Should be interesting to see what it makes - Are you going to run a vacuum pump ??