[RICK LAKE]

blackout Mike I will try and keep it simple,
weight of car?
amount of HP you are looking to get from 390 motor?
rearend ratio?
What are you doing with the car? cruising, autocross, 1/4 mile racing??
Need a rough percentage of car's usage?
size of tires for rearend?
Without this info is a ball park answer.
Would go with a trans ,if stick with a 2.80-2.60 1st gear, depending on rearend ratioand overdrive for cruise with a .87 od again depending on rearend ratio. These numbers would change depending on rear.
Other thing is motor power. If you are building a stock 275 hp motor and the car weight is 4,000 pounds, going to a higher 1st gear will be needed to not have to slip the clutch to move car.
See putting wrong combo's togeather and you have a car that runs poor, can't get out of it's own way, doesn't cruise well, and eat gas at 10mpg.
Bring on some more info. Rick L.