With all the types of antifreeze out what would be a good choice for 72 455 with A/C and aluminum rad?
Use any of the green A/F. It tells you right on the container it mixes with all color A/F, and protects all metals. Stay away from Dexcool (Orange)
You shouldn't ground a radiator. It should be insulated from the core support. If you ground it and your engine, or any other component ground becomes corroded, you will have potential current flow through the radiator which will cause it to fail. I'm not aware of any modern cars that ground the radiator. Even transmission cooler lines now use a rubber flex hose between the steel lines.
HAFTA GET THE TUBES ULTRASOUNDED EVERY YEAR NOW ! DANG! No more aluminum radiators allowed in competition without certs... Imagine the logistics. Dang, crud, shoot, heck, wizz... Personally I would not ground the radiator or heater core; maybe a sacrificial anode. I have a 15,000 lb battery so I guess I dont know nuffin... ws
I recommend you error on the side of changing the coolant every year; so don't bother blowing your budget on something expensive.
I agree on not grounding, and also on insulating the radiator from the support. Aluminum and steel don't like each other. The idiots at GM put aluminum wheel well opening moldings on my '82 chevy which are causing electrolysis. They shooda used stainless as some Buick models had. I know that it wooda cost more, but still...
