Bob,
I am building my '52 3100 shortbox with a 261, 3:55 gears, Saginaw Tranny, dual intake and split exhuast. I went for a ride in one of Patricks trucks and I was sold on this combination.
It has been a blast working on the old iron and seeing how things were built back then.
If your thinking about building a 261 give Patricks a call and they'll give you more information then you can stand.
http://www.patricksantiquecars.com/ Aaron