Have not built one, but have a couple 261's set back for a future build. I've got some bookmarks of stuff I've read..
http://www.angelfire.com/nv/conv/stovebolt.html

http://webrodder.com/article/stovebolt-stroker-chevy-six-part-1-history-of-the-stovebolt-chev

Good luck on your build..
Mongo


Mongo's Garage
Vintage GM Truck's & Parts
https://mongosgarage.com