Don,
I gave you the combo for that in our first thread of discussion- you didn't listen to it then, so why should I bother to repeat myself?
882 heads are garbage, throw them away and use a quality set of heads. Those have a factory flaw in the intake runner design and flow for crap. your performance, as well as mileage will suffer.
If your going to run those heads than there will be no differance if you run 11/2 or 1 5/8 or any at all. Your worried about exhaust flow from a set of heads that are worthless for flow.