This sounds stupid, but I can't figure it out.
Which way does the clutch disc go in?

I have the ACT Street/Strip disc, and one side is flatter than the other. Also the shaft sticks out more on one side.
Any help?

 

It should say on the clutch disk. Like: To flywheel

Hmmm let me go outside for a sec.

It looks like the disks flat side goes to the flywheel and the protruded side goes to the pressure plate side.

Anyone want to confirm that?

 

I too have the ACT set-up you mention and it is pretty easy to figure out which way the disc goes.

Lay the disc on the flywheel and it will either rest flat on the friction surface (right way)

Or the center spline section will be resting on the pilot bearing (wrong way) and keep the friction surface from touching the flywheel at all.

 

Most clutches have Flywheel side embossed in them, see if yours does.

 

My ACT set did not....