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ok, just found this out, if u have a 327 block, you use a small journal crank (283) if your using a 350 block you use a large journal crank...

Go here, it'll tell you everything you need to know about chevy 302's

http://www.geocities.com/MotorCity/Garage/1020/chevy302.html

Ok what i know is,
a 283's crank in internaly ballanced, doesnt use a harmonic balancer, so you wont been that, but you might have to use a 283's flexplat/ flywheel just when u do this
make sure u...

Do a seach on yahoo or google,
sure you'll find exact instructions on what to do...

putting a 283 Cam in your 327 wont do shit to the displacement.
but a crank on the other hand... i believe you put a 283 Large jounal crank intoa 327 and you get a chevy 302, there two different...