Help Me Put Together A Rotating Assembly!

[AmericanZ28]

Hey all, Im trying to help a friend piece together a rotating assembly for a blown 96 Z28 Automatic. This is an internally stock LT1 that had a vortech supercharger kit installed a few years ago. The engine recently spun a bearing, so he wants to build a solid 383 bottom end in anticipation for better flowing heads and increased boost later down the road when funds permit.

For the moment, I think forged internals are a must, but I'm not sure if a 6" rod would be ideal over a 5.7" rod for this application. Also, what compression ratio should he aim for for use with pump gas. The goal on the supercharger is 8psi.

One last question; whats the difference between internally and externally balanced rotating assemblies. Is there an advantage/dissadvantage to either?

Thanks...



Im not exactly sure what model vortech it is as he lives in another country and communication isn't ideal, but this is what it looks like.

[35th_camaro_ss]

there is alot of variables that can be done, I believe alot will depend on the budget looking to spend

as for internally and externally balanced, the goal is to balance out the rotation assembly and if this can be achieved by just machining the crank weights, this would be internally balanced...sometimes its needed to balance using the flywheel and harmonic balancer making it externally balanced.

Al

[AmericanZ28]

there is alot of variables that can be done, I believe alot will depend on the budget looking to spend

as for internally and externally balanced, the goal is to balance out the rotation assembly and if this can be achieved by just machining the crank weights, this would be internally balanced...sometimes its needed to balance using the flywheel and harmonic balancer making it externally balanced.

Al

Thanks for the response. The budget is between $2000-2500K.

He will be using the stock harmonic balancer and flexplate, does that mean the crank will have to be internally balanced?

[35th_camaro_ss]

I think really you should find a reputable local machine shop and they can better help guide you through the process.

Al