If it were mine I would do this. Learned the hard way be careful after porting the 906 heads on my 451 I asked the machine shop I used in Az to dress the valve seats and cleanup the head gasket the charged me like 300 because the heads were as they said "all f'ed up and cut at some angle" so they had to remove the angle (with out asking they just added it to my bill), as I had cut the intake to match the heads I had to cut it again to rematch what a pain that was if I had done all my cuts on the heads it would have been a lot better. Again I have to say BJR is spot on here.