Has my chipper come back down-rated?

[monkeybusiness]

The speed showing on the box is possibly determined by a feed sent from the engine's alternator, and is therefore related to engine rpm (not directly determined by flywheel rpm). If the pulley sizes have been changed it is possible that the flywheel speed is still the same (therefore chipping speed and draught are also the same) but at lower engine rpm. It may be that the replacement engine has a more suitable peak torque at lower rpm, hence the need to change pulleys to increase flywheel speed at lower relevant working rev range.