Late A headers on an early A (smallblock)

If memory serves, all of the exhaust manifolds
and headers in the chart were tested on the same
engine with no other changes .
It was done to determine the flow characteristics
and power potential, not really to promote any engine build.
At least you would have a benchmark/baseline to help make an informed decision.
Might be helpful to someone reading this thread in determining what they could use, maybe not to others.

Hope you can find a header that will meet your needs without too
much modification and expense.