I will TRY? to attach a pix of a ECZ D head with a 57P casting number. 1955, very similar to the ECZ A,B,C head. As you can see the Chevy 1.94 valve fits the chamber and although I did a little grinding on the outer 1/3 chamber at  the intake valve head Radius it was not necessary. I just had my die grinder out. Ford valves of 1.92 will drop right in. Check the SHAPE of the combustion chamber it screams Chevy HiPo and is VERY STONG. No posting is necessary with these heads. Pete

Carl,



1. Later "G" heads might be "posted", and would stand up better when flogged (head gasket failure). Though the larger valves would not flow more at high RPM (shrouded), I think the deck would be thicker than "C" heads milled to the same CR?




6 VOLTS/POS. GRD. NW INDIANA

Carl:

If it is a street car, I don't feel it is worth the extra money.  Decking the block for 0 deck height will raise the compression and make it less fuel sensitive.  If he is desperate to put G heads on it, I have a pair that need some guides replaced and a general rebuild.  But again, for street use, unless he wants to brag about his big valve heads, I can't see any advantage.

John 

John - "The Hoosier Hurricane"

John   you dont think it is worth the effort of putting bigger valves in the c heads. he is just trying to get some more power for his 55    Carl

Carl:

The C heads are reported to flow very nearly the same as the Gs, so unless he is going for maximum horsepower at 6500 rpm, he probably won't be able to tell the difference between the two.

John

John - "The Hoosier Hurricane"

the 192 valves are too big for the heads so to get them in you have to enlarge the chamber to get the larger seats in.  probably use a die to open the area up.  carl

Hello, I do not see how installing larger valves will change the size/volume of the ECZ C heads one way or another. The valves are closed at Compression stroke and the valve head becomes part of the Cylinder head chamber roof over the piston.

a friend is building a 56 merc 312 engine for his 55 crown.  he cant locate a set of 57 g heads so his thought is to use the ecz-c heads and have the 192 valves installed in them.  my thought is he will increase the combustion chamber size to much.  any opinions on this would be greatly appreciated.  carl