g37 coupe piston slap
 

Looking to bore a vq37vhr block, don't know too much about them. The engine however was experience piston flap before and was ran on it for a good time.
Need help with measurements and possibly to know if it's even worth fixing. Automatic trans too; these blocks can pack a punch for sure though as I seen some on YouTube.

I would suggest to take a pen/paper and start mathing.

The amount of labor and work it will require to properly bore and rebuild a VHR is way over what a replacement would be. Beware that the "piston slap" noise that most folks convince themselves with is usually VTC issues that make it sound like piston slap however is the cam gear unable to set the right timing on one bank.

Boring will increase the size of the bore meaning you'll need new pistons. In other works much more than $800 which is what you can find a newer VHR for and install and continue with your life. There are many ways of messing up a VHR rebuild.
The reason they are amazing is that Nissan took their time to properly select the and set the best they could for it. Many times people set clearances for the "just in case" when it really was never needed.

I get a replacement engine might be scary or a waste however these are the current cards to play in 2024. The time will come where rebuild will be cheaper but for know peace of mind and risk of getting it wrong are lower with a replacement.

You're going to be pulling the engine either way, so you might as well go with the "cheaper & easier" route of a full replacement motor, unless you already have the machine shop labor for free (i.e. you're the one doing all the work and don't have to worry about tools/space/manpower). You might also ask yourself why you want to bore the engine out in the first place. If it's for repair or maintenance, go with a drop-in replacement. If it's #BecauseRacecar, there are better options for making more power. Probably still gunna want that replacement engine, though.