spd hammer,
alot of turbo choice depends on what your goals are for the engine.
you said 200hp was a goal. that can be achieved without a turbo.
if you want to pursue the turbo idea. a blow thru system is a better choice. the drivability will be better and you will be able to intercool the air. a 60-1 turbo should be a very good choice for a 250 cu motor. tom
