Hard Exhaust Seats on a 390
#1
I know this has been discussed before.  First of all I am freshening a 390 that was built back in about 1980.  I was only driven about 200 miles and has been parked since about 1986.  I am now in the process of installing new valve springs and valve seals on the cylinder heads.  I am using springs Comp suggested for their hydraulic flat tappet cam I am installing.

Here is the issue I have come across.  When the these heads were rebuilt back in 1980 hardened exhaust were not installed.  Of course back then pump gas still had some lead in it so the valve seats look just fine.  Are hardened exhaust seats really needed for a car that might only see a few hundred miles per year?  I get conflicting information on this.  Some say Ford's castings are a harder alloy so it's not as critical as GM castings.  Any information is appreciated.
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#2
Hi Mike,

My Mustang heads do not have hardened seats installed for 2 reasons.  The guy who machined the heads didn't want to take the chance of ruining the HIPO heads.  He said if during the process he hit an air pocket in the casting the heads would be no good.  Second, he  indicated if hardened seats were absolutely necessary with today's gas he said he would have a line down the street for business. So I took his advise and did not have hardened seats installed.

So for what it is worth I am on year 5 with my Mustang and drive it only on the weekends during nice weather and have not had any issues.

Mike
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#3
Thanks for the information.  Your Fairlane turned out nice on a reasonably budget so I am trying to do the same and not spend on items that won't offer any benefit for an occasional fair weather driver.  The valve tips on the exhaust valves are worn for some odd reason.  But I can get new stock size replacements that are finished and ready to install for a reasonable price from a place called Alex's Parts.  My plan was thoroughly clean the heads, replace those exhaust valves, and install new Viton valve seals and the springs the Comp Cam's tech recommended.  I've tinkered with valve springs enough to be able to set them up at the correct heights and loads.  I was stuck grappling with the exhaust seats, leave as is or have hardened seats installed.  Plus, Redline makes a lead substitute that gets good reviews and the mixture is only 1 oz. per 10 gallons of unleaded fuel.

I need to post a few pictures of this project.  It's a 1956 Ford F100 pickup.  Yeah, an old fat fendered Ford.  It was a frame off restoration in the early 1980's.  Body, paint, frame, suspension, brakes, motor, trans, and drivetrain were complete in about 1983.  It was driven a little around town, maybe 200 miles at most, for a few years.  Since then, it has been sitting in a garage (that was rarely opened) for 33 years, never moved, never started.  I had to buy tires and wheels to move it.  The old right rear tire was stuck to the garage floor.  It's slowly cleaning up and looking a lot better.  But, I'm surprised how dirty it can get even in a pretty much sealed environment.  The original chrome from 1956 is not bad, but the chrome from the early 1980's is terrible.
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#4
Mike,

Sounds like a neat project.  I like the old fat fender Ford trucks.  Please post some pics...I am very curious to check it out.

Mike
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#5
Yeah it is a nice project.  I've been working on it a little over a month now.  I nice change from a small car plus there as there is lot of room to get to anything.  I like that everything seems to be much more simple too (I guess I'm getting old).  There are now a lot of reproduction parts for it and the so far the quality of them seems better than those for Mustang reproduction parts.  Only draw back I've come across so far it that parts for big block Ford motors are more expensive and not as easy to get as for small block Ford motors.


I took the Mach 1 out for a ride a couple of days ago.  When I opened the hood I forgot how little room there was.  I wondered how I ever got the entire car assembled.
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#6
Oh yes, big block Ford parts are a whole new price catalog.  At least it be something you can compare the performance to your Mach 1 to. If my memory serves my right your Mach 1 has a 351, correct?   Unfortunately, I just put my cars up for the winter.  We had our first snow and they put the nasty salt on the roads.  That's when I stop driving them.
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