I have a tbi 305 in a 91 bird. I have nearly everything I would need to convert to carb. including an edelbrock 600 and a performer intake. What kind of gains would I see from this switch? how much would it affect gas millage?

Maybe some HP gains, but gas mileage is sure to suffer. Don't forget you need to provide means to lock up the torque converter when the ECM is disabled by this change.

You really need to address exhaust, cam, & heads to see real gains from the switch.

Merrit Island? I visit your neck of the woods when the company sends me down to the Cape. Will be down there in about 3 weeks.

nm