Don, yes, you have to swap the main drive gear and the pinion gear from a 408 (helical or Gleason gears) to turn a 308 into high speed (408) gearing. They swap perfectly, everything else remains the same. Pinion gears are tricky...I completely take mine apart and re-lube...careful, there are 34 very small ball bearings in them...then you have to get the Pinion gear just the right tightness when reinstalling on to the rotating head....should have just very slight play in the bearings (don't overtighten)...I lube them with HotSauce...you'll ever need to lube them again...well unless your dunking in salt water frequently
