which one would be "better" to swap in to on my z6 block? i have an option of a ported and polished d15b vtec or a z6 out of an si that has a comp cam 59300 in it? ive been reading up online and it might be possible to put the cam from the z6 into the d15b but then theres timing issues?.. and ive only swapped a cam like twice so im still pretty unsure about doing it. last time i had some valve/engine chatter.