305 oil high milage bad vavle seals

[Problem2420]

well guys my firebird has a 305 with bad valve seals a 205k miles on it, for the mean time i was wondering what weight and viscosity oil is best for the smoking i was reading 20-50w but would that be okay for california climate. i was also reading marvel mistery oil would help. i know htere are some engine experts on here that could help alot of us high milage people out. lol

 

[trailer-trash]

in my experience marvel is a good product.....but it made my old nova burn worse than before...it may have "cleaned" it out too much haha...Id substitute one quart of oil for a quart of lucas and keep driving it...Many a GM has been known to burn alil haha..

 

[Problem2420]

yeah i know i want to seafoam it but im scared it might clean it out a little too good and something bad happen. lol im going to replace to block later just for now im tired of the smoking on start up

 

[JonZ71]

either do heavy oil or replace them