Have an 8" Dynamic behind my 505.
3.54 gear
B&M 11 x 11 x 1-1/2 tranny cooler mounted in front of the radiator. 3/8" line in and out.
About 400-500 miles last year.
Highway with 3.54, 28" tire is:
3,200 = 67-68 mph
3,300 = 69-70 mph
Would I drive it to California from NY...probably not.
Would I drive it to work, the gym, afternoon cruise..... sure do.
I notice it will wind out more than my 9-1/2 from a dead stop and hills on the highway, I attribute some of that to the weight of the car and the 3.5 gear.....but flat or mild inclines are fine.