Hi All, I'm using as a daily driver my 85 trans-am with a carbed 355ci. I'm running around 400hp and I'm using this car as a daily driver 55 miles a day. I've read that fuel could be saved by tuning the IFR putting a wire in and or smaller Squirter and pump cam..I've aleady gone from 70 main jets to 67. Any idea what could improve fuel efficiency with this carb ?? Thanks lot .

Fuel efficiency has nothing to do with the tune unless the carb is poorly out of adjustment. A properly tuned carb will give a required 14.7:1 air fuel ratio while driving to a roughly 12:1 rich WOT. Reading the plugs or using an O2 sensor is about the only way to know how well the carb is tuned. You can also have the emissions tested to fine tune the carb. The squirter and pump cam give an extra shot of fuel when the butterflies open to compensate the lean transition. Too much or too little fuel and the engine will bog.

Randomly changing things can usually make things worse.

Not all carbs are the same. You can take all the 750 carb models available and get different performance or economy results with each. Some carb models get better mileage than others.