Having first aftermarket crank balanced and want to confirm what I need to bring to machine shop or other advice if recommended.

Crank is a Eagle cast 360/3.58 stroke supposedly at 2050 bobweight (I know - a junk crank but only need around 380hp & it was free to me)

The new KB-107 pistons have rings installed, are pressed onto rebuilt/resized stock rods w/caps+bearings & ARPbolts+nuts all together already. I had planned to bring these 8 assemblies along w/crank to the machine shop.

This is an internal/neutral balance setup (right?) so I shouldn't have to bring Summit balancer or B&M flexplate.

I want to get at least a static balance - figured this motor/crank isn't worth the extra money for dynamic balance job for the little hp that I'm expecting.

I am also hoping this combo will balance w/minimal cost as I will buy new rods before I put Mallory in that cheap cast crank.

Opinions/Advice?

TIA

you'll need , 1 upper & lower rod bearing, 1 rod, 1 piston & pin, 2 clips [if using floating pins], 1 ring package for the piston, and the crank.

!!!!BUT they will need to take all the rods and weight check them to make sure they all weigh the same!!!

the pistons should not have been put on the rods prior to balancing. the piston/ring/pin assembly is weighed and matched. the connecting rod big (plus bearing) and small end are weighed independently and matched. the small end is reciprocating the big end is rotating. the whole point of balancing is to do a dynamic balance. weight matching the parts doesn't really get you much without spinning the crank with bobs on it and making the necessary adjustments. i would think trying to match the pistons with them on the rods is just about impossible to do accurately. i would be suspect of any shop willing to say they can properly balance that assembly.

I was afraid of that - was hoping I could use this crank without much effort. I was mocking up for final assembly when a buddy gave me the crank. Will probably go back to the external balance setup & use the crank in another motor.

i'm not familiar with the parts you have so i have no idea how much potential imbalance there might be. that said a 340 i built close to 30 years ago that had no balancing done was flogged in a race car then sold and installed in a challenger street car...it's still running. this was however with all stock parts including replacement TRW flat tops so the weights/balance were probably closer than what you're working with.

Even though it's nuetral balance engine, still take the balancer and the flex plate with you to the balancer. They will still want to check the balance with them bolted on.

Like what was said, the rods need to be off the pistons.

I don't believe that is an internal balanced crank. My advice would be to put on a damper for a 360 on and put it together. That bobweight is very close to what a stock 360 is with KB 107's. J.Rob