Replacement 68 340 four speed cams

These cams run best in High-Compression engines, or in clutch cars because of the loss of cylinder pressure at low rpm. Neither can hardly be called "radical". To get the numbers, they have really long clearance ramps.
For the 268s;
The wide LSA (114) allows the rpm to hang on at the top, I have seen dyno curves where the power plateau is about 1000rpm, which is huge! But it comes at the expense of absolute power.