Howdy PI:
There will be at least two areas of concern in using the same header on a 200 and a 250. 1st, the 250 block is almost 2" taller than a 200, and 2nd the 250 has a low mounted starter, while the 200s starter is mounted above the oil pan mating line. Both exit very close to the starter. There are also some variations in starter size.
If the swap works without modifications, you will have to be very,very lucky.
What vehicle is this in? That could also be an issue.
Adios, David
