First off, I am not arguing, just saying what I have experienced personally.
I bought my '68 GT350 on April 4, 1972.
Unleaded ethanol has been around since about 1975 which I have always used.
The only advantage that I found to using SUNOCO Racing gas, if it is an advantage, is that the car will immediately idle down from 800 something to 700 something.
I do not like the white lead deposits it leaves on the plugs and the valves or on the observable portions of the exhaust system.
My experiences with the original gas tanks is that they need to be kept as full as you can get them for storage, not the opposite.
Most of my 68 GT350 has used "Aeroquip hose" since around that time and 304 ss hard tubing where applicable so that might be a factor in the results with those components?
About the only original fuel hose that I can think of that is still on the car right now is from the fuel pick up to the metal fuel line outside of the tank. It is still original. Has been off of the car and examined and still un-cracked or showing signs of interior deterioration.
What you have experienced and that you share with others is appreciated and I note it. I can't deny your experience.
The carb valves show no evidence of foreign materials on them. They just show a mark where the rubber meets the metal ring of the seat.
I have also had issues with failed power valves but that isn't a recent thing. It is an on going phenomena. That goes way back to my start... and yes I do use the check valves installed in the throttle plates even when not original to the carbs.
I invested in a Moroso "power valve" check tool and my initial experiment of 12 brand new, "still in the bubble wrapper packaging" showed 50%, yes half, had vacuum leaks brand new, so really what needs to be factored into that equation is the quality level of the original part or the lack of quality in the original SERVICE parts?
One probably does need to take into account my location though. There are places on the Earth where the compass does not work. In one case it is called the South Seas Anomaly. Who is to say there isn't another location where the normal laws of physics do not apply and right here in the NYC area could be one of them? After all, to some, I defy ANY sensible logic?
On other vehicles here, everyday use cars, many of the "rubber" fuel lines have been replaced. There are no "factory original part numbers" on them and are largely NAPA parts. So far, so good...knock on wood, but simply put, I have not experienced any of the side effects others are describing in over 49 years, so color me cautious but respectful of others more experienced then I am.
With these "bumps of knowledge" on my head and if one is truly wiser by making mistakes and learning from them, I should be, but am not, in the "genius" class by now and still the general consensus is that I am just the "Village Idiot" and we just "humor Doug"? That's actually ok with me since I long ago learned to accept that and at least get invited to the barque afterwards.. .even though?
After all, I am 75 now and don't look my age. I only look 74 so it confuses people because I still use words that are no longer in the vernacular, but I still remember them AND so far only one person has threatened me with a gun and he was just a medical doctor so that is likely understandable anyway by his own piers?