I talk to John several times per week. 443-250-9037 mobile, 410-357-0185 home. His website hasn’t been updated in a long time so do not use his old Essex mailing address. Use 20540 Green Rd, White Hall, MD 21161-9075 instead.
Also, another email address that he uses is sentinelpilot@yahoo.com. That is the one to use if there are any attachments such as photos and it is what his L-5 club membership is tied to.
(p.s. it’s an oil pressure gauge, not gage. :>)