Thirsty 400!!!??!!

[Ticker]

I'd tend to check the A/F ratio before looking any further - if you've got a performance shop nearby or even an emissions/tune-up place they can probably get some readings for you. The assumption here is that the timing is done right - the first thing to check.

Q-Jets are great street carbs if properly rebuilt, but it's not unusual for them to be gas hogs due to wear - or leaking out the bottom plugs. It's worth spending the money to have them professionally rebuilt by one of the few shops that do it right (see my .sig) as typically at this point they need a fair bit of TLC to work as designed. Do no - do not - buy a rebuilt from NAPA, Schucks, etc. - they'll be complete garbage.