First of all, do you have the vacuum hooked the manifold port (below the throttle plates) NOT the ported carb port? They wont shift smooth, if at all, on the wrong port. And yep, I HAVE hooked a C4 wrong port.

Lokar shifters are vague at best. Being tall, I often rest my knee on the shifter lever and end up in second. To do it again, I would opt for a cable shifter with positive detents - and may yet. Great shifter, but needs better positive detents, a subject that I have discussed with Lokar a couple times