500 "ported" heads

[pete500]

Due to coolant leak I removed the complete intake system yesterday. To my BIG surprice I found the ports in the heads to be around 2.5mm (1/10") NARROWER than the ports in the bottom-plate holding the injectors. This makes an critical obstruction for the inflowing gas, and might be one of the reasons why there's so big variations and relative low output of the 500's. I don't know what to do, it's not enough material in the heads to open up the ports to a good smooth fit, probably I have to make a complete new manifold. pt