I have recently acquired a Norvin project that has a rear head with an exhaust port that has been machined to a size of 2.0" x 20 TPI, the front head has had the brass insert installed as is outlined in KTB bringing it to a standard 1.88 x 20 TPI, it appeares as though the lack of a rear insert was intentional as the engine has been rebuilt and is propperly mounted in it's frame. My question is, does anyone make an oversized exhaust nut to fit the 2.0 x 20TPI and if so does this pose a threat with the thinner wall of the port?
Thanks
Thanks