The small block Chevy dampner will work on the 250 but you will have to machine about a 1/4 inch off the crank side of the "snout" that fits over the crank. I have run a Fischer, an ATI Super Damper, and a Fluid Damper all with good sucess on a 292. They share the same timing cover so I don't see why it shouldn't work. If you are going to spin the engine very fast it is a must. The one 292 I shift at 6800rpm and have never had a crank problem.

1964 Chevrolet C-20 Fleetside, Otis
1950 Chevy 1/2-Ton, Kirby
1950 Chevy 1/2-Ton Shortbed, Walter