Correct way to Balancing pistons

I am not sure if this is the right place to put this but here goes.

I have had a machine shop build me a LT1 383. It has SRP flat top pistons part# 138093 and 6inch rods. I had it internally balenced but when I got the assembly back. I seen what looked like they took a drill bit to the underside center of piston crown and drilled to wt match not all piston have been drilled on. And some have been drilled in more than one place. Is this the correct way? Or one of the ways you can do it. How much weaker does that make the piston if any? Also I told him I was going to spray it with a 250 shot if that makes a differnce. I have a picture of what I am taking about if you need to see what I am talking about. They are in my car domain site in the sig on page 2

I checked out your website Cliff and it is darn near impossible to make out the extent of work from the pics.

When you say they were drilled... which area was drilled. Is it the area directly under the piston crown or is it through the non-thrust sides (near the pin bores)?

Can you take a picture of the area?

-Mindgame

It is the area directly under the piston crown. They are a well know shop locally. But ever since I seen how they balenced them. I have had the question if that was the right way. But I never asked on here due to the fact that I had faith in them and really did not want to find out if it was done wrong. I did not see this until I got it home and started putting it together. But I can not quit thinking about it so I am trying to put my mind at ease. I also have a friend that is going to let them do the work on his motor and I want to make sure it is done right before I let him take his motor there.

I can not take another picture as the motor is in the car. Waiting for a new camshaft as I was sent the wrong cam. And the DCR is way to high for me to run the engine

I sent you an email of a picture maybe it will show up better.

Somewhere on the underside of the piston is the most common place to balance them. When I had my old LS6 BBC pistons balanced, I couldn't see the balance machining once the rods were on.

Thanks Cliff, you've got mail. :)

-Mindgame

Thanks to all who replyed. :bow: I can now put my mind at ease now. And I am glad I asked. THANKS