ALTERKATION AND BIG TUBE HEADERS

Ok guys, The project is getting closer. I was told last night by my fabracator to
be ready to order the front alerkation kit with in the next two to three weeks.
My question of the day is, with all this new found room I will have up front
what kind of header can I now use? Will a header from a B or E body fit?
We have cut the inner fenders out so all I have to contend with is the down
bars from the fire wall to the front frame.

The engine we arre transplanting is is a blown 440 (BDS 6-71), its a mild build
estimated hp around 750. I have been told I need at least a 2 1/8" tube header
and a 2 1/4" would be better. This engine is not mine it belonges to my fabracator
who is also a good friend. I have a 440 plans in the works that will have the 8-71 blower
and hope to be in the 1000 to 1200 hp range sometime in the future (1-2 year plan)

Any help? ideas? suggestions? On a last note I have a set of flowmaster 40's I will be
running at the end of 18" long collectors when I dare to drive the beast on the street.
and will play around with collector lengths and open exhaust at the track. I have found 18"
long collectors to work best for me with my old 496 stroker.