Quoting Egalloway:
Bc cams are not that great. Two shops that have awd tuners close to me won't touch them without adjustable cam gears to allow correction. On the other hand they both said kelford and GSC cams don't need them. They both stated the bc272 cams cause crappy idle and in general low gains. Dyno sheets of users show the low spiky gains of them vs the higher end kelfords or gsc cams that produce big gains across the power band.
Suggestion from someone gone through similar issues. Pull the head send it to dale (bogussvo) and ask him for some insight. He is a huge resource and the man when speaking of the 2.0 head. If not toss the cams for some kelford 264 or gsc1 and retune with a tb rebuild you started good.
Not following the stock profile, like HKS/Kelford/GSC do, cause the need to dial in to zero (think Web Cams for the old-school guys, forgetting the fact that they used to self-machine themselves down to perfect circles ;-) ).
As Pot stated, decking the head and/or block will put the 0* slightly off. However, think of it in these terms: A 4G64 swap, with a 6mm taller deck height puts you at a 3.75 degree difference, which is only 1/2 tooth (360/48 teeth). Your not taking 6mm off of the deck or head on a 4G63 (or should I say, if you do, you'll have bigger issues than cam timing..). So you'll only have a slight variation caused by decking the head or block.
This is why Mitsubishi came out with the MLS head gasket. It wasn't for "performance" and it's not a Ralli-Art part. It's a TSB part to compensate for engine rebuilds where the head and/or block was decked (cam zero, quench height, compression...). That it happens to hold up really well is just a bonus.
Josh