Yep, he has no proof that any oil change at 6 months is safe! Why not every 3 months? Where does it end?
The OP was asking about corrosion protection and some of us have given him some suggestions with data appropriately addressing those concerns…
ps. We need pictures of those cars 😉
Thats old hat. Amsoil has had superior corrosion protection with their 15w40 AME (diesel/marine) oil since I don't know when. Not sure if many oils can best that one. 🥴
Amsoil Z-Rod hands down with 3 grades to chose from….
HIGHLIGHTS
Engineered for classic vehicles
Helps retain horsepower
High-zinc formula protects flat-tappet cams, lifters, rockers & other critical components
Protects against rust during storage
Have you cranked it with the starter, plugs out? Crank it till it’s cleared out. Replace the plugs and get it fired up. After some warmup, take it for a drive. Tell us how she runs…,
Did the annual oil change on both my Reds this past week. Amsoil out, Amsoil in. Maybe 40 hours on each this year due to power outages and exercise runs.
Before the oil change I did check/adjust the valves on Big Red for the first time. Maybe 150 hours on it and the exhaust was a little tight...