Looking for first chevelle

[txchevelle35]

Hi All,

I've been using this forum for the last few months researching my first Chevelle purchase. Looking for a 68-69 hard top coupe.

There's a lot of knowledgable people on here so I was hoping someone could help with a few questions I've run into.

Since Chevelles were built in the 60s, they had to use Leaded gasoline. I heard that since the only gas availble now is unleaded, using unleaded will damage the engine unless certain valves are replaced. What valves need to be replaced? Can an classic car inspector verify that the valves in a Chevelle are up to date and can use unleaded gas?


Thanks for any assistance ya'll can provide


Rob

[carpoor]

Install hardened exhaust seats in the heads. That is all that would need to be done. These cars are so old now, that unless it is a "survivor" that has never been apart - most have had the heads R&R'd at some point and have had this done by now.

[earthquake68]

Very true. Even if you had the early, "soft" valve seats, you won't drive it enough for it to matter. I have a '67 Impala with the original 283 and soft seats. It hasn't had leaded gas in it for 25 years and it still runs fine. After all these years, it just puffs a little smoke on start up. .....which is valve guides, ....not the seats. .........and an inherent 283 problem, regardless.

The first year for case hardened seats is 1974 or '75. If you car doesn't have the original engine, I can almost guarantee it has hardened valve seats.

.....and to answer your question, NO. You can't tell if an old set of heads has hardened seats installed by looking at it. You have to tear down the engine and physically look at the seats and valves in the engine to see if they were replaced.

The bigger engine killer is alcohol in the gas. The old carburetors DO NOT like having alcohol in them. An aftermarket carburetor like Holley or Edelbrock have more modern materials inside them and can take the alcohol a little better. Try to stay away from alcohol in gasoline whenever you fill up.

[brassmonkey]

You are on the right track. NO reputable shop would allow a set of heads to go out without putting in hardened seats.

So here's the deal - if the car runs right when you buy it the valve seats wont give you any trouble. If it needs to be rebuilt then the builder (machine shop that does the heads) will install the new seats w/o even asking you - its just what is done today.

My opinion - worry more about rust than the old valves.