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They will physically fit and function, however, you don't want to. The primary reason is combustion chamber size, which is substantially larger than early 289 heads, causing a loss in performance. Also, there will be little or no difference in flow, meaning no gain in performance there either.

All Ford heads had flame or induction-hardened seats since the 1950s. Unless damaged or ground-through during previous rebuilds, they will be fine with unleaded fuels. Standard 'hardened seats' from machine shops are no different than what is in there now, and it costs big bucks for exotic racing valve seats that street cars don't need. The primary causes of valve and seat erosion or recession is poor fuel and/or poor ignition tuning. Rich mixtures cause pitting or grooving, and retarded timing (especially at cruise) causes valve erosion and valve seat recession.

David
 

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Discussion Starter #3
Thanks
the only reason was i dont want to take my car off road while i sorted the valve seats in my heads so i could run unleaded petrol 95ron . i was told by the previous owner that i needed to use and lead additive as it had soft valve seats. now im confused wether it has or not . help please.
 

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No, you do not need a lead additive with today's fuels. What you need is a really good tune of both your fuel and ignition to prevent valve and seat issues. Rather than re-type a bunch here, try this thread for more insight. Follow the additional links there for some interesting reading. There are many references online from large testing labs and engine associations that are specific about what causes valve and seat wear and what does not. Unleaded fuel does not.

Unfortunately, there is an Urban Legend about unleaded fuels that just goes on and on, and a small but profitable market that serves it. For those that think additives are still necessary, I would like to offer some of my own formula of Home Elephant Spray. I tested right here in my house, and sure enough, I have not had a single elephant bother me. $20 a can or $200 a case plus shipping. Guaranteed with a full refund if elephants invade your house.
;)
David
 

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Discussion Starter #5
thanks i will read that at weekend and see if i can get my head round it.

can i but 2 1/2 litres of you elephant spray please i will pay you by western union money transfer from my cousins wifes brother in nairobi if thats ok lol
 

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LOL... no I'm sorry, we only ship to addresses in Nigeria.
:D
David
 
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