Main clearance is pretty high at .0045". Probably why OP is low. Rod clearance is kinda high also. Still, at 15psi idle/50 psi running oil pressure is not dangerous low. I might be tempted to run it and enjoy it while you plan and collect parts for your next build or re-build. A high volume oil pump (I think you have standard volume?) would help the oil pressure situation somewhat.

Piston to wall clearance should be set based on piston manufacturers recommendations + engine builder experience for piston and alloy type and application. This will not affect oil pressure to any meaningful degree.

Also, FWIW, 4.375" is an over bore for a 400 block. .035" from memory.

Why did you have this done?

Why not back to the original builder?

Who did the first dyno run?

Who did the second dyno run?

Once the oil pressure is fixed, what is wrong with this motor? And exactly what problem are you solving by selling this motor and starting over? A perceived piston rock problem? If you do another motor, will you use the 3rd builder that tells you have 30th piston to wall, or will you get a 4th engine builder?

BSB67, I had it done because I wanted to double check the bearing condition because the solid roller cam was not installed properly and it kept eating the distributor gears. We found the end play 1/16th. I figured lets double check everything since we have it apart. That is exactly were the problem started. I should have left it as is.

I am not having any luck with engine builders. The first builder is out of business.

The second one dynoed the motor the first time and the second time. Great guy but I don't trust him. He built another big block chevy motor for a friend and the clearances are also all wrong. The guy builds full out race motors but I really think he isn't the best at street motors.

I was only thinking of building something new to fix the short piston, and lowering the compression.

I could fix what I have, but I might have to get custom pistons to lower the compression.

It really sucks paying people over and over but I can't find a good engine builder. The third engine builder has been around for years building street motors. He has done a lot of Chevy motors but I don't think he does a lot of Mopar builds.