we are planning a rebuild of my EAB this winter. i'll be the owner/helper/gopher. i've got two good mech friends, one who has done flatheads. i have a mercury crank i'd love to put in it. i have one set of EAB heads (on it now) and a set of 8BA heads. the 8BA's were on my old engine that had the merc crank. is there any advantage with either set? do we need to worry about clearance? i think the 8BA and EAB's are both ford heads?? i do know that i need merc pistons for the merc crank and i believe the rods are the same ford/mercury?? thanks, trying to get my ducks lined up. dick r.

 

You're all set if you get Merc pistons and use the EAB heads. EAB and 8BA heads will both give higher compression than 8CM heads. (desirable) Rods are the same between Ford and Merc. Sounds like a nice upgrade!

 

I'm with Ross , assuming you've had both sets of heads magnaflxed and you did not end up with too many really big cracks .

 

The EAB's are a little more preferable but the 8BA's will work ffine as well. The 8CN's are the early Merc 1949, into 1950. Then the 1CM's are the 1951 on and into the EAB's up to 1953.

Here in Canada the EAB's were used in the 1953-54 Flatheads.

Just be absolute that you use the Merc Pistons, they are just a little off from the 239 ones.

 

When putting a new combination of rotating assembly and heads togeather it's not a bad idea to clay the pistons.

 

Okay don't ever recall hearing that term before "Claying The Pistons"

Is there aanother term for it, or exactly what is the meaning?

 

Onec all the new stuff is togeather, except the head you put about a 1/4 inch ball of clay on a piston, install the head and rotate the motor thru a full cycle - Pull the head and carefully remove the clay - measure the thickness of the clay and see if it meets the piston/head clearence you want/need - It insures that when the engine heats up and things expand they arn't going to run in to each other.

With more info and pictures
http://www.flatheadv8.org/clayhead.htm

 

EAB heads are the highest compression commonly available factory head for the late flathead Ford. Use them.

For more flathead compression ratio information than you know what to do with, get the pdf from here: Flathead V8 Compression Ratios...6,020 choices - The Ford Barn

 

Where do 8RT heads fall on the compression spectrum?

 

8RT heads are supposedly the worst, with lower compression (by a small amount).

 

What about 59AB's?

 

---and after 60 years any of the heads could have been shaved to true them up---

 

59AB's are the pre 48 heads. Don't think that they'll work on a 48-53 block.

 

You can make 59-series heads work on an 8BA-type engine, lots of guys do it for the nostalgic look. Just requires plugging a hole on the driver's side bank. But the 8BA style heads (and blocks) have a better cooling flow pattern.

 

Here is the first of thirteen pages of compression ratio calculation:


Apparently the 59A(B), 8BA, 8RT, and EAC heads all have the same 76cc size combustion chamber.