Flex plate clearance issue

[ClassicIron]

Hi everyone, I tried to do my due diligence to find if others have had this issue but came up empty. I have a 383 Stroker with a 168 tooth flexplate and new PowerMaster starter. When I installed the starter I discovered the starter gear was already contacting the flex plate even before engaging/receiving power. Taking a closer look the flex plate is also extremely close to contacting a rear main seal stud on the back of the block. It also measures much closer to the rear of the block than all my other small block 350s, leading me to believe this is a flexplate issue, not a starter issue. I confirmed with my engine builder the flex plate was correct (Pioneer FRA-159) and oriented appropriately (raised pads facing converter). So what could have caused this? I’m looking at a flex plate spacer as a possible solution but I’m resistant because this shouldn’t be an issue to begin with, maybe I’m overlooking something... Any help is greatly appreciated!