I have run the 261 cam in both the 235 and 261 engines, both instances I was happy with the idle quality which was set at 475rpm. The cam has good low end grunt and mid range torque too, a happy balance if you ask me for a truck. After putting a couple hundred miles on the 261, I'm pretty much in love with everything about it, best inline I have owned.
Steve


1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration