Don't know if this will help or confuse but I have fitted a 625 Street Demon with the composite bowl to my stock 289 powered 66 .[ $316.00 from Summit ]. Went real well straight out of the box but a bit rich. Fitted the next size up metering rods and went one size down on the jets. Had it analyzed before and after and O2 readings are near perfect. Starts , runs both town and highway really well with better throttle response. It is on a Weiand Street Warrior manifold. My nearest parts store is Summit in the US , only takes a week or two to get bits to NZ !!