Head Milling Size

[Powerhouse]

good idea...i'll try that and see how much I have left. I just took 50 thousandths off the head last week.

kinda weird that this thread is almost a year old and I just got around to shaving it.

[Powerhouse]

Just did the clay on the valve test...seems really close. The stock head width was 1.93...it's now 1.85. It was cut on a precision cnc machine...so I guess it's OK. Just seems really close. But .010 is a very small space. Anyone else cut a head .050. What does it measure???

[1942cowdodge]

I had my head shaved in the military and they did it for free!!!! Anyway just thought I would plug that in and I really have noticed a difference in power since I had my flat head six shaved this past winter. Now I can cruse at 50 and not feel as though I'm running at full throttle. Oh yes they took oft ..060":D

[Powerhouse]

ha...thanks

[Flatie46]

I pulled the head off a spare engine I have and took it to work to check it for straitness. With it just laying on a flat surface it was warped. I put it on the magnetic chuck of a surface grinder and with the magnet turned on it pulled down strait. I figured the bolts would pull it down more than this so I left it alone. Did you run into this on yours?

Edited May 22, 2010 by Flatie46

[Powerhouse]

Mine was perfectly straight...it ccd at stock specs...so I took the .050 off as instructed by the book. Hopefully it is ok. time will tell

[BeBop138]

I took 65 thou off mine and put in 50 thou cut in the valve area on the head. To add to the mix---will this affect which plug to use---I am using Champion RJ12C---any clearance issues.........Thanks.............Lee

[james curl]

When I built my engine in 2006 I had the head milled .100" and clayed the valves and saw almost zero clearance on the valves, only in the combustion chamber radius on the port side of the valves. I used my rotatory grinder and a 3/8" round burr and tightened the radius in the combustion chamber above the valves. I ended up with .060" clearance over the valves on the port aide of the valves. The machine shop surfaced all mating surfaces on the block enough to be flat, so they took some off of the top of the block also. In almost twenty thousand miles of driving I have not encountered any problems in the head area. Hope this helps.

PS: I would not use Champion Spark Plugs in any thing that I have to depended on if they furnished them free and paid me to use them.

[Frank Elder]

James, do you require higher octane to run your flatty since you upped the compression?

[BeBop138]

When I built my engine in 2006 I had the head milled .100" and clayed the valves and saw almost zero clearance on the valves, only in the combustion chamber radius on the port side of the valves. I used my rotatory grinder and a 3/8" round burr and tightened the radius in the combustion chamber above the valves. I ended up with .060" clearance over the valves on the port aide of the valves. The machine shop surfaced all mating surfaces on the block enough to be flat, so they took some off of the top of the block also. In almost twenty thousand miles of driving I have not encountered any problems in the head area. Hope this helps.

PS: I would not use Champion Spark Plugs in any thing that I have to depended on if they furnished them free and paid me to use them.

I take it you don`t like Champion plugs lol---what plug are you using now and what gap---with my HEI my gap has run the best at 50 thou.......Lee

[james curl]

AC 44R or Autolite 603, .035". I just have had lousy luck over the years with Champion plugs, even in my lawn mower.

[james curl]

to answer Frankie, no, I run regular. I am almost deaf in the high frequencies and could not hear it ping if it is. I have had other people ride with me and listen while placing the engine under high load and none of them heard anything so I assume that it is not.

[Powerhouse]

Hello all...

I just did the solder test on a stock 47 head...with the gasket in place it doesn't even touch the solder. without it the solder gets a crimp of about .075 and thicker.

The 51 head I shaved .050 will not work for my particular application because it's a bump head and I am rebuilding a non bump block...so i'll have to shave the other head as well now.

[Young Ed]

I take it you don`t like Champion plugs lol---what plug are you using now and what gap---with my HEI my gap has run the best at 50 thou.......Lee

Lee thats a common thing around here. I run those champs too. Between Dad and I we must have 10 flat heads all running them. Never had an issue. Mine in the p15 have about 15k miles on them now.