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· Registered
9,084 Posts
Lead substitue,that depends completely on if whoever rblt the motor/heads had hardened exhaust valve seats installed at the time.

There is no way to tell if this was done that i know of unless the heads are off the motor.

So to be safe i would run the lead substitue to avoid the possibilty of burning your exhaust valves over time. This is fairly inexspensive to do yrly considering how much we spend overall fooling around with these cars.

I was using a std over the counter lead substitute for over 25 yrs in my 69 396 before i rblt it 2 yrs ago and it did a good job of lubricating the ex valves & seats as they looked to be in real good cond (Per my machinest)when i tore it down for the rbld. But i did have the hardened exhaust valves installed in the heads when i have the valve job done.

Maybe you could find out from the prior owner/s what machinest rblt the heads and call them him to see if they always installed the hardened ex valve seats as std proceedure on heads that needed them. This would answer your question if they ALWAYS installed the hardened ex seats in heads when needed to run on todays unleaded fuels


· Premium Member
5,584 Posts
Discussion Starter · #5 ·
mr 4 speed said:
My 454 does not have hardened seats.
I use a little bit Marvel Mystery oil and some lead subsitute (from the local prts store,can't remember the name)

I do this like twice a year,thats about it.

Don't overthink it :)
Hey Chris,
Your pic looks familiar HamdenPlaza ???
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