What are the differences between a blower that is set up for alcohol and one for gas. My guess was that the tolerances on an alcohol blower could be closer due to the cooling effect of the fuel.
Most anything that is not a strictly pleasure, non high boost thing is anodized.
Gas looser...yes....heat reasons as above.
A gas piece after run..you can cook an egg on the case. An alcohol piece is nice and cool...hence clearance differences.