Those Running 3.73 And a TF w/ LockUp.. What's your highway Driving Like?

peachtop said
I have 3.73 gears in my '47' Canopy. I'm running a 46rh behind a 340 and I cruise at 60 mph all day and the RPM is 2000. My tire diameter is 27". The only problem I see is very little torque at that rpm so it takes a little more throttle when going uphill. The gas mileage isn't that great. I thought it would improve when I replaced the 727, but it actually went down.

Exactly my point in post #33 in regards to an A8. If your motor won’t work well at the lower cruise RPM’s that the taller rear gear and OD offer, it can make the car worse. And sometimes it isn’t tuning but more just the engine build.

peachtop said
I don't care what v8 you're using, none of them have any torque at that rpm unless you are running with a very small cam and a very light car. The engine has to have a decent amount of torque to keep the vehicle moving into a headwind.

Just have to point out that a 2015+ 6.4/A8 runs at 1560 RPM or so at 65, and sometimes in 4 cylinder mode. And they make 485 HP, so I don’t think it would be considered a “very small cam” motor nor is a Challenger/Charger a light car. And it pulls fine and gets something like 23 mpg.

Not saying it is an apples to apples comparison, but pretty sure the ‘73 Duster I am going to put a 5.7/T56 in will be fine cruising at 1600 RPM just like the ‘15 R/T did before I sold it.