Deciding on a gear ratio

[69grande351]

Hi everybody, I have decided to go with the gears. But I don't know what kind of gear ratio i should get. I would like to go on the highway sometimes, but dont want to blow my engine up. So do you think 3.55's would be a good choice? Also, do you think I should get a posi? Or should I wait and upgrade to a nine inch later on and then get a posi with that. I will not be on the drag strip so the et times arent a factor. I also want to but a 600 cfm Holley carb and edelbrock manifold. Is that a good setup? Would my car be faster with the gears, carb and manifold? It has the stock 302 w/auto and the stock 2v carb. Thanks everyone.