Ok this should be easy so I will get staight to the point. 1969 Olds 98 455 F block C heads yada yada. I have been doing some work on the engine bay and motor , mostly fresh paint gaskets and seals. I did change the timing chain and gears plus the tranny filter. New fuel pump all new hoses and vacuum lines. Last year I noticed that it had a little puff of smoke on startup but I was also doing a lot of cleaning the carb to get it running better. I added guages and found that it idles hot at around 15lbs. which I was told that was ok. What should I be using for oil and should I be adding octane booster to a tank of fuel. Also is a question of lead substitute do you guys use it on a 69 455 I did notice a little chatter on acceleration. Someone had said you can add ATF fluid to the fuel as lead substitute , is this a good idea? What brand of ATF fluid do you use for a 69 th400 , I noticed 2 types of GM fluid in the store 1 is for pre 2001 ? It is also3 times the price so is there a particular brand that is better than another? Brake and P/S should be straight forward I was mostly wondering what weight oil and how important is the tranny fluid. Plus will ATF in the fuel help with the valve chatter or try to find a lead substitute?