Any specific reason you desire to run 555cid? And why the nasty converter? I am not ridiculing but want to help, it's nice to know where and why you have these numbers planned out. I like 4.500 bore with 4.325 stroke and keep the converter down to 4000. I have built this combo for the strip a few times and the combo is very compatible to every car they've been in. I do like the alloy head idea also. Is the 34 going to only see the strip? No street driving?