Been debating this with a buddy and he says he's certain that 6th gear is used for mostly cruising only. He says on a stock or fairly stock t56 if you're reving the engine into the higher rpms that you wanna go no higher than 5th gear. Any truth to this?

 

You will gain no acceleration by going into 6th.

 

Right but can 6th handle doing like 130? Without damaging anything?

 

I would have to say you could cruise at that speed in that gear, I think. However I would not condone it.

 

5th and 6th gears are designed for economy use. Can they be used for other purposes? Sure. I have seen them explode before from someone using them to race.

 

^^^ This. Both 5th and 6th are overdrive gears: http://en.wikipedia.org/wiki/Overdrive_%28mechanics%29

You will be able to go faster at lower RPM with them, but will see a drop-off in power.

 

It would depent on what specific ratio you are talking about. In the C-F4 T56 2.66LGR set, 5th is the weakest , for example. It is purly dependent on the gear design.

 

Now the stock 5/6 gears are indeed for economy use, but how many of us use them for economy use . Now you can run the closer 03-04 cobra 5/6 gear set and they would probably benefit you at higher speeds. But back to what Calhoon stated its going to be based of the actual design of the gear that determines its strength.

 

You will have to change the mainshaft for an Aston Martin 30 spline shaft and bore the tail housing to run the Cobra 5th and 6th gears though.

 

Good Point Jeremy