Bob, why [and perhaps what] do you ask? Are you able to get a good deal on a FM engine or what?



Per the GCR FM can run either a 6-port 13B or the Renesis and they are built and sealed by SCCA-approved builders "with no modifications to the engine or any of its accessories or components."



Sounds to me like a pro-built ITS 13B would be faster.
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I was always under the impression a FM had a street ported 4 port. Thanks for the info!