I would imagine that lwaving one shaft in would be far worse than taking both out! The I understand that the shafts "balance" each other out, as well as engine vibration. Leaving one in might make the truck undriveable!

I balanced the connecting rods and matched the pistons when I did my rebuild, so it may or may not affect the vibration I feel. On a scale of one to ten, with the engine with both safts installed being a 5 (and the higher you go the worse the vibration) I would put the engine with the elimination kit at about a 5.5 or 6 -- I can barely tell a difference, if at all.

Some others who have eliminated the shafts without balancing have had more vibration, but I guess it depends on how out of balance the engine is to begin with.

The hardest part of installing the kit is removing the timing cover. The shafts pulled from my engine with only a hefty tug with my hand (after removing the bolts, of course).

Terry