I rebuilt my 400 a while, back and was reading an article that said you should rebuilt the valve seats to accept the newer lead free fuels of today> I never did this before assembling the engine. Should I have done this prior to assembly and do I have to worry about anything else in relation to it internally other than valve seats. I would hate to have a cracked head or something later on and have to pull everything apart and find more components. Plus, I don't have the engine installed in the car yet either, so now's the time if I have to do something like this.

Makes me sick if I have to rip everything apart, but it would give me a good excuse to change the cam to a longer duration and possibly bore it out even more than what I had done originally.

 

Not valve SEALS, valve SEATS are what need to be changed for unleaded fuel. All engines built since the 1971 model year have hardened valve seats for this reason. You can have a machine shop install hardened seats in your heads, but in reality, you probably don't need them. All that will happen is that you might need a valve job after 75,000 miles instead of 100,000 miles.

 

I think that's what I said, right, valve seats. I honestly don't remember what the seats look like and if they were changed out by the previous owner. How would you know? Anyway, do you know how much they charge and if this is the only item that one needs to worry about.

 

When I read your post, I read valve seats. you would have to take the heads off to tell. I'm with Joe, if you are not driving this car lots of miles a year, I would not worry at all. Also you used to be able to buy fuel daaitive for this. May not be avalible any more? My son has a 68 W30, and we did not change his seats, did not want to take a chance of someone ruinning a set of D heads. He used to run additive, but I think he quite.