You dont need to loose the Offy valve cover if you use a spacer & you still might need to round off the corners of the first & last rocker arm.
A couple guys here make them.
As far as lump or no lump, well, when you are forcing air/fuel into a cylinder, your cylinder head design is less critical.
Adding lumps will help, so it would be worth doing.
Too bad Tlowe did not compare a non lump head when he turboed the 250 on the dyno.
MBHD
