Paul,

    The posts are in the water jackets between the flat part of the combustion chamber and the top surface of the head. You can see or feel them through the water jacket holes on the machined face of the head.   

Frank/Rebop

Bristol, In ( by Elkhart) 

How can I determine if 57 G heads are posted?  Can you reach into the ports and feel the posts or see them?  Can you tell externally, markings, date codes?  I know my 57 312 was manufactured in March of 57, so it shouldn't have posted heads.  I have two  sets of G heads, one pair loose and one set on an engine.  The set on an engine are a bit of a mistery.  The engine is a 272 with a crossover pipe.  I thought 57 passenger car 272's exhaust crossed over after the engine.  Could it be a truck engine?

Thanks,

Paul J. - '57 E Code

The G heads are typically around 69cc’s if unmilled or that’s at least a good value to use if not cc’ing the heads to get an exact value.  On a stock bore 292, these heads will net about 8¼:1 CR with a composition head gasket while on a similarly built stock bore 312, the compression ratio will be 8¾:1.  Both of these engines are with a flat top piston and sitting at 0.020” in the hole.  Adding a 10cc dome to each without any other changes makes the compression ratio for the 292 jump to 9.27:1 and 9.84:1 for the 312.  These values just give you a rough idea of what the compression ratio numbers look like with these combinations but you’d need to recalculate using your specific bore size and deck clearances for a more exact compression ratio.

Lorena, Texas (South of Waco)

I have found a set of 312 ECZ-G heads. Thay have been fluxed and all that and look brand new. Thay are according to the guy almost flat at 004 ea. If I purchase these what pistons can I use on them? They come with rockers .  

55Birdman  Hickory NC

Sorry.  I have no extra heads available.

Lorena, Texas (South of Waco)

You have a pair of these to sell?

55Birdman  Hickory NC

The 471 head is a ‘big’ truck head and came equipped with the larger 1.92” intakes but the combustion chambers were in the 82cc range.  Don’t know the exact year they were introduced but should be 1958 or 1959.  And there’s additional information that some of the ’59 Mercury’s equipped with the 312’s had these also.  This is the head of choice when putting a blower on the Y as the larger combustion chamber requires less work in regards to piston choice in getting the compression ratio lower while mantaining some measure of quench at the deck.  And this head also works great with domed pistons in keeping the compression ratio low enough that it's pump gas friendly with minimal dome modifications.  Under the water ports you'll find '5750' on one end and '471' on the other.  Here's a couple of pics.

 

Lorena, Texas (South of Waco)

Birdman,

Go to Mummert's site and look at the head chart link, print it out and carry it with you when you look at motors, heads etc. I carry a copy in all my vehicles along with other vin code info etc so when I come across a car on the side of the road I can decode it on the spot.

The 113 and 471's were not made in 55 - 56, they were a later replacement head for the G's.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Ted, Are you referring to the 56 471 heads or 113 heads? Car or truck.

55Birdman  Hickory NC

As has already been brought up, other big valve heads besides the “G” head are the 113’s and 471’s.  The 471’s are more conducive for use with the domed pistons as they have a larger combustion chamber and tend to be more pump gas friendly without dome modifications.  All the 113’s and 471’s are also posted whereas only a small percentage of the ‘G’ heads are posted.  The 471’s also already have hardened exhaust seats due to their intended use on the heavy truck line.  But the slightly smaller valved 1956 heads are also suitable for a performance upgrade with the intake valve sizes either being left as is or replacing with larger diameter valves with the appropriate seat work to go with the size change.

Lorena, Texas (South of Waco)