I am having a Mercury spec engine with a mild cam being built for my Ford F1, I have the options of putting the Ford heads on and it will look Ford, or I can have the Mercury heads on it and have the wow factor when popping the hood open.


The truck is not a hot rod and will never be, it's just a fun driver.


Any thoughts?


Scott in Texas

 

8CM Merc heads have larger combustion chambers, resulting in the same compression ratio (a miserable 6.75:1) when used on the 255 Merc engine. Putting the Ford heads on increases CR to 7.3 when combined with a .030" bore. If you have Merc EAC heads (will be cast onto the heads) then there is no difference. The best stock heads are Ford EAB.

 

You will have more compression with the Ford heads.
Mark

 

Ross types faster tan me, he beat me by a minute.
Mark

 

I will place my vote for the Mercury heads. They may even be higher compression. I have a mercury tailgate on my F350, because the bed came with it. I get more comments on that Merc tailgate than all the difficult modifications and rare features this truck has put together. BTW, you are gonna love that 4" stroke when you visit your old familiar hills in your home town.

 

And you both beat me to my erroneous conclusion!

 

Scott, there are some simple things you can do for cheap with the heads (either ones) to really give your engine some snap. Not simple to describe, PM if you're interested.

BTW "r_reed" on here has a stroker motor with some other mods, check his posts to see how much he likes it!

https://www.ford-trucks.com/forums/1...r-is-done.html

 

I agree with Ross the EAB ford heads should yield the higher compression.
I have a set of milled eab heads on my rebuilt ford engine but have yet to run it.

I have always thought ( and im not sure where i supposedly got this info) that the merc heads would yield a lower compression than a ford head but i think this is only if you ran a merc head on a ford motor, then you would end up with the lower compression? Hmm anyway.

I forget, are you having Roger install hard seats? If so i would run the 8CM merc heads if you do decide to go with merc heads. I just like the sound of 8CM vs EAC. Plus the EAC engines didnt have hard seats from the factory.

Im not really sure how the 8CM engines were rated at 110 hp but the EAC engines were 125hp if i remember correctly.

Cheers
Josh

 

It is cool to be a little different , but I am biased