I did measure the stand-off length. It is .800 or 800/1000 of a inch. I choose that length so the exhaust will be close...but most important.... I can adjust the fuel mix through 2 , 1/8 holes drilled just back of fire wall. It works out good. I am going to get a better exhaust later. It is ok for anyone to use any photos I place on RCU....I did it to try to be of a help. Best Regards Capt,n