Hp don't mean anything as its all in CFM and at that time tne biggest they offered was 350 CFM which will work fine on the big lunged ancient airplane motors but we need free high flowing carburetors, about 650 to 700 CFM is about right.
 
 
I'm not following you here.  Why is 180 HP more CFM for us than for an O-360?   I just sent them a question to see what the bore diameter is on the top 3 sizes they list.  I did notice that there was a FAQ on the Ellison page that says they don't recommend auto fuel, since it could damage components in the TBI.  I'm not sure how much this is real, vs CYA.  Ellison doesn't seem all that much in favor of auto engine conversions in the first place.  Rusty (already talked to Van's once today, danger, danger)