I bought a super light flywheel from tweakit.net and i got a dual friction centerforce
but once you put the compts together there is a gap just over a 1/2 inch between the mounting surfaces

Is there some mounting kit need for this setup?

 

Yes, there are supposed to be round aluminum spacers that go between the flywheel and the pressure plate. At least that is how my racing beat light steel flywheel was setup. I would try calling racing beat and asking them if they still offer a hardware kit for a light flywheel. They should be able to fix you up with something that will work...