Yeah I agree.. with those numbers, your headgasket should be good, check your oil and see if it is merky/brown. That's weird since it is blowing white smoke, b/c that is a good indicator of a blown head gasket.. As for your cam positioning sensor, those fuckers are cheap and the seal on them are thin. It could be that or even leaking out of your valve cover, b/c mine did that and I thought it was that sensor. You are definately gonna have to get your exhaust mani machined, no way really around that w/o replacing things. With the amount of money you will spend fixing your head, it'd be alot cheaper to fix it than replace it.. But it's your call. As mentioned before AutoZone has a good return policy :).. g'luck man.