[sexypizzaman]

So I bought my 383 INTERNALLY balanced rotating assembling and I have a question. Does this mean that my entire rotating assembly is all balanced already in relationship to eachother (pre-assembled at factory and balanced)?? I remember on the phone they asked me if I want the kit balanced prior to shipping and I said yes because in my town there isn't very many machine shops. I am confused however becuase I keep reading posts that people are saying you still need to have it balanced eventhough I already bought a rotating assembly that is internally balanced!! Why the hell would it need to be done twice when the parts are still brand new???

Can some1 please clear this up for me it is really pissing me off because I don't want to have to bring the block back to the machine shop and have them piss around with it anymore.

Thanks alot for any input,
Keith

[bondo]

Basically,........

Whether it's Internally,......... Or Externally balanced is Irrelevant.......

That means the sum of the total will bolt-up,+ run to About the original factory requirements..........

Now,..... If you paid Extra for Matched Balancing of the Components of your "Kit",.....
There should be documentation that tells you the Tolerances used.....

[xntrik]

Originally Posted by sexypizzaman

So I bought my 383 INTERNALLY balanced rotating assembling and I have a question. Does this mean that my entire rotating assembly is all balanced already in relationship to eachother (pre-assembled at factory and balanced)?? I remember on the phone they asked me if I want the kit balanced prior to shipping and I said yes because in my town there isn't very many machine shops. I am confused however becuase I keep reading posts that people are saying you still need to have it balanced eventhough I already bought a rotating assembly that is internally balanced!! Why the hell would it need to be done twice when the parts are still brand new???

Can some1 please clear this up for me it is really pissing me off because I don't want to have to bring the block back to the machine shop and have them piss around with it anymore.

Thanks alot for any input,
Keith

Internally balanced means it uses the flywheel and damper WITHOUT big balance weights on them. You'll have to see if your crankshaft is for the 350 flywheel internal balanced center hole. (External balanced 400 hole is 1/2 inch bigger than 350 Internal balanced hole.) You might need a 400 flywheel special made WITHOUT weights.

If you paid for the component SPIN-balancing, then the crankshaft should be matched pistons, rods, etc. already.

As Bondo said, there should be a "balance card" included in your kit giving the exact weights of components and the "bob weight" used to balance the crankshaft.

See if you can find an experienced person that can look at the pistons, rods, and crankshaft and tell you yes or no that they have been "spin-balanced".

[curtis73]

Balancing is always a good idea, but I've built many low-po engines without even checking it regardless of aftermarket rods, pistons, pins, rings, cranks... its a wise move for reliability and smoothness at higher RPMs (and power) but for 90% of what I build I just know that pistons are matched, cranks are balanced, rods are within a gram or two.

I just bought a 400-hp-capable vortec shortblock that was not balanced. I'm going to run it at 325 hp or so and I won't fret a minute about it. So I guess what I'm saying is... you're ahead of the curve if you've had it balanced. Don't worry about more balancing. Even if they took your money and didn't balance it, I would bet you'd never know the difference.

[Richard H.]

I think you are good to go except I have to tell you this. Ironically I got a call from my machine shop today about my new flex plate was welded on out of round. Now this is an external balance and he said he could finish with an OEM till I got a new one but would rather wait on a new one to make sure it is above specs. For the life of me I can't remember but on your hopefully new harmonic balancer it should tell you what to do with the removable weight to insure the right balance.

[sexypizzaman]

Hey guys I just looked in the crankshaft box to see if I missed any documentation and sure enough I found a peice of paper folded up that is titled "customer balancing information". It states the rotating weight reciprocating weight and then a summary of the bobweight. I am assuming this is the peice of paper that tells me it has been balanced. If I am wrong please correct me and if not I thank all of you hotrodders for your help.

Thanks again,
Keith

[PatM]

Sounds like you're golden.

Pat