You stated that it runs real well, if you have a significant leak on the underside of an intake gasket, I think you would notice low vacuum and poor running. You could pull the spark plugs and keep them in order, then compare plugs with each other. If one or more plugs looks oil fouled, you may have a leak but not very probable.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
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