ive just picked up a T2 for my swap, the engine has an act clutch disc, act preasure plate, and act light weight fly wheel. when i pulled the motor from the tranny to check it out and make sure it was what the P,o said it was, i pulled the preasure plate off and the bolts retaining it were very loose almost just handy then there is the fly wheel and then what looks like a counter weight.

ive only ever been messing with 12a's and am unfamiliar with the 13b.

my ? is on the 12a the counter weight is located at the front of the e-shaft. should this counter weight be in front of the flywheel. and are these act parts worth having? ill post a pic of what im talking about

 

Most aftermarket flywheels need to bolt to an automatic counterweight. The stock manual flywheel has a CW cast into it. ACT stuff is a common and excellent upgrade on TIIs. I run the SS/HD and a streetlite flywheel on mine and love it. Assuming the stuff you have is in good shape I would most definitely keep it.