LD4B how good and how rare what are they worth?

I have tested the LD340 on small port heads. The reversion thingy is crap. Ur motor is an air pump. The heads are doing the sucking, so to speak. The 318 actually picked up a few ponies and tq. The only way u will get reversion is if u have a hood scoop sealed to the carb. Kim
Kim, have you tried the LD4B on the big port heads?