i've heard that the combustion chamber walls around the valves on the ecz heads need to be ground away to let the engine breathe better. has anyone ever gotten into this? if so,could you tell me how you went about doing this? thanks a lot

 

I haven't heard about the "shrouding" issue. Maybe it would be better and more effective to replace the cam with a different grind.

 

it was something they did with the 57 G heads.i have read that unless your going all out you dont need to bother.im sure others will know more.

 

I am trying to recall this from memory, but I believe that the ECZ-G heads were somewhat shrouded, but the 58-59 "113" heads had a slight relief that eliminated the problem, or at least helped. Also as I recall, Mummert's flow test work didn't show very much if any flow difference between the two styles of head. I don't think it was more than 5 cfm, and if this is the case, your are only looking at a THEORETICAL 10hp on the top end here.

On the other hand, the relief will cost you several CCs in chamber volume, and I would guess that for anything that is run on the street, the advantage of hte compression would outweigh the slight loss in top end breathing.

But, if you decide to do it, a 113 head would be the thing to use as a template for your starting point.

When you get to fiddling with grinding on heads, even slight changes can affect flow. So, unless you know what you are doing precisely (i.e., you know that the change you make WILL make a positive difference) or you have a flow bench to check your results, I would be inclined to suggest you not bother.

Incidentally, some folks have espoused the need to relieve the block, putting a chamfer at the top of the cylinder to match the overhung chamber. This also costs compression and puts a "dead" area in the chamber that stays unscavenged. The tests I've read show it's a waste of time.

If I were you, I'd be talking to Mummert on this, if you are serious.

 

If you want to get going with a grinder then I suggest equalizing the chamber sizes. Ive measured a full +/- 3% from nominal spec on a pair of the same castings. It is very easy to get within +/- 0.5cc.
By cc'ing first you will also get an idea if and how much the heads were milled over the years.

Ford was always sloppy on chamber tolearance, the flathead V8 was all over the place too.