The marks in the pic are where I’ve scraped away the wax oil with my finger. There’s no evidence of any rubbing prior to fitting the BRBs. I’ve wrapped them in split silicone tubing.
My tester is a good man, old school and understands old cars. Been using him for 30 plus years.
There is no alternative place to fit the just fire and aft by maybe 1/4 inch.
