Interest in a run of 300/340 shorty headers

There are several different headers that are close to what we need, unfortunately most of them have too large of a port.I guess that's why I am leaning towards the 302/351 Ford as my starting point.My supplier doesn't know when the Rover headers will be in so I might as well tinker with this idea til then,cause there's no guarantee they will fit either.
First off,port sizes are virtually the same.As I had mentioned before,port spacing looks workable.
Buick
| | | |
4 1/4 6 1/8 4 1/4

Ford
| | | |
4 3/8 4 3/8 4 3/8

Port angle relative to deck-
Buick -48 degrees
Ford -60 degrees
The 12 degree difference(the Ford is more straight up) can be compensated for when you cut the flanges off.
I'll have the frame in the shop on the weekend and I'll be able to put my motor in and check for interference .