That is about what I had figured on my Bolens G152 with the 1330 single stage blower, about 1,000 rpms with the engine at full throttle. (which is 2800 rpm on my two cylinder diesel) My gearbox is a 4:3 reduction. (75%)
The reason I bothered is I increased the auger speed by almost 25%. It really throws snow, but sucks power like mad, and I can't turn it off fast enough to prevent damage if the shear bolt doesn't go.
Kind of goes without saying - more speed, less power.