Yer been on that merry-go round of changing things, it can be hard to get off. Good thing on the return lines. I know with our fuel system all of the returns will be logged individually.sometimes it goes forward,then backwards. I've chopped up the exhaust to lay them back another 10 degrees to try and help push the front end back on the ground. Re doing part of the fuel system. A fuel car guy said I should put a second flow meter on my return lines.Now I'm making a manifold to feed all the return lines into one so I can measure the fuel return.It helps keep track of the return rate so if we have a blocked check valve it will show on the data logger.Just keep throwing money at it.
Ordered a spare engine block from England