Engine treatments & Synthetic oil
 

Has anyone used the Rislone, Sea-Foam, Slick 50, Lucas or other treatments?

I have an '83 Trans Am, 305/Cross-Fire engine, with 40000 miles on it. I drive it less than 1000 easy miles a year. I'm getting ready for the annual oil change. I think I have a bit of lifter noise on startup. Do any of these treatments help or hurt?

Also, I'm getting ready for the annual oil change. I'm thinking of switching from 10w-30 conventional to 10w-40 synthetic oil. Any nightmares there?

THANKS