There are two basic Q-jet castings, the "750 cfm" and the "800 cfm". The only real difference is in the size of the primary venturi. The primaries were opened up a bit on the 800s to get the extra flow. Without two carbs to compare side-by-side it can be difficult to tell whether you're looking at the smaller or larger venturis, but there is one surefire way - pull the carb, turn it upside down and open the primary butterflies. The 750 has smooth venturi walls all around the booster rings. The 800 has a "bump" in the wall of the venturi adjacent to the booster rings.
The numbers are on the driver's side of the carb on a flat between the primary and secondary side of the carb. Remove the aircleaner and get in there with a flashlight and you'll find them.
__________________
----------------------------
'72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car!
'73 Firebird 350/4-speed Black on Black, mix & match.
|