Thanks everyone. I'm already using the correct thin head bolts.

I guess I will have to shim the converter with washers. However, I dont like this method and never had to do this with any other 727 brand converter... Seems like a Band-Aid fix to me frown

One would think that instead of asking the customer to shim the converter that the core would be machined to correct this or a different core would be used by the converter company.