That 9.5 was designed for up to about 300 ftlbs, and You know a 5.9 Magnum makes that probably by 3500 rpm, probably less.Anyway, that 9.5clutch and the short-arm pedal are a match , therefore, you shouldn't have to mod it to the aforementioned 6inch pin-to-pin measurement.
Instead, look to the fork-travel, that it isn't hitting the rear of the window.
And also to the Z-bar orientation; that it is installed parallel to the ground and at right angle to the centerline of the car. And that at the transmission end, it parks far enough forward that it will pass thru plumb at about half-de-clutched. And that the adjuster-link, also at half-travel, is about parallel to the ground.
If your install hits all these marks, and your disc is known not to be warped, and the engine mounts are known to be not-torn.Then
you will have to actually measure the clutch departure. You need to have at least .080. If you do not have the minimum .080 departure, now is the time to mod the pedal
But if you do have the .080 minimum, then:
It may be that the clutch is dragging from; an out-of-alignment bellhouse, or a tight pilot bushing, or the input shaft is jammed into the back of the crank, or the clutch pedal is not parking properly at the top of it's stroke; Or, I suppose the disc could be in backwards, or hanging up on the splines.
If none of these apply, then IDK.
