Elgin E293-S It is a solid lifter cam finding good hydraulic lifters is tuff. It is about the same as the Corvette cam.
Switch to solid lifters and go with a corvette grind. Works very well. like sunbeam said, the new hydraulic lifters seem to be problematic.
Later 235's use the same grind as the 261. There seems to be a shortage of 235 cam blanks for new grinds, so you'll need to use YOUR cam for a regrind. I have a couple used, good, cams I'd part with - send me a PM. Tom Langdon at Stovebolt Enging Co. has a 'Bulldog' grind that seems to work well. All the current cam grinders can regrind your cam. My '57 is running a 220@.050 / .450" lift, idles well - even with the stock carb n intake! I like SCHNEIDER CAMS here in San Diego, lots of experience with vintage engines. Go with a SOLID grind, as there is no good Hyd. lifters available - unless you score a NOS set on ebay...