Hello  Redoing a pair of 471 heads. Have heard these have flame harden EX seats. If true, are all 471 heads this way or only in trucks? In cleaning them up I can't notice any difference with carbide burr. Thanks

I'm inclined to say that unless they are not OEM, the seats aren't hardened. Leaded gas was being used. Replacing exhaust seats became common when the lead was removed. 

Not pertaining to seats but when I had my heads off last year I bought the positive seal tool from comp cams, machined the tops of the guides with the tool and installed seals. I only needed to clean the chamber and lap the valves as they only had 10K miles. The engine never ran as good as at it did after the guides were sealed in my opinion. It was easy to do with just a drill and I only cut enough to miss the retainer keepers + .025”. I used the seals that metal only touched the guide. Just a suggestion. I think the tool and seals were less than $100. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

All the ‘471’ heads I have dealt with had the hardened seats.  Those particular heads came off of HD 292 truck engines.

While I’ve had core engines arrive at the shop with 471 heads that had all appearances of being last used in cars or light trucks, those engines were previously rebuilt making it questionable as to the heads being original or not to those engines.  Because they do have hardened seats, many of those heads survive much better than the run of the mill heads.

The parts catalogue does not show those heads being used for car use.  With the 471 heads having a 10cc larger combustion chamber than the 113 heads and a 13cc larger combustion chamber than the ECZ-G heads, it’s doubtful that Ford actually factory installed any of those on passenger cars or pickups.  The compression ratio would be dismally on the low side.

But the 471 heads are a good choice for where the compression ratio needs to be lowered as in the event or a supercharger or turbo application or where an older set of domed pistons are being used.

Lorena, Texas (South of Waco)

Hello Thanks for Info. Ted.    Heads were off a 59 mercury. How do I tell if they a harden?  Like I mentioned could not tell any difference in hardness when cleaning up. Plan on having  everything done ( new  valves  IN OS,  positive seals, EX seats, bronze guides). Heads were really rusty may have to put a seat or two intake side as well, will see if they clean up. Going down  S/C road is why I need them.  Drylake  any idea why your engine does run as good after upgrade?  Cos

I’m guessing the umbrella type seals helped with bypassing oil vapor. The umbrellas were not staying on the guide boss but going up and down with the valve. All the piston tops were carboned up and had to me looked slightly wet which I wire brush cleaned. Plugs were ok and I use that type of seal on all my racing GMC 6’s so I figured why not. The guides and valves showed no wear after micing the id of the guides and the od of the valves. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.