3.08 is a good ratio with 253 4 speed as it still has enough that you dont have to ride the clutch and it brings revs down on the highway...ive had a few 350 chev t400 vehicles with 2.78 and i just put a 3.08 behind the same driveline and its much better..not as sluggish...mind you it had 3.55 which was great for lightin em up..