Head milling max?

[345Dart]

Opinions/facts required on what is the maximum amount that can be removed from a SBD 308 open chamber head before one runs into sealing problems (or other problems) - compression will be no more than 10.8:1. Presently have .100 from head surface to flat of combustion chamber.
I see Cuda273 in another thread has removed .080 from his 273 castings. Can the same amount be safely removed from an open chamber design?
thanks

[jelsr]

Can't help on the max amount (my info is all BB) but pay attention to the oil feed to the overhead. It comes in at an angle and when larger amounts are removed from the surface the alignment of the two holes suffers. Enlarging the holes slightly will keep the lube flowing.

[440barracuda]

howabout for a big block 906 head??

[73440charger]

my bro found this in the MP Chassis Book

[73440charger]

trying attachment again

[440barracuda]

Nice, just allitle to small for me to read though.

[jelsr]

The BB heads are a 5 bolt pattern so they are supposed to be superior strengthwise. The engine book refers to removing .060" as an example for CR's and states the CR obtained from that much of a cut. It further states that cutting any more will cause oil restriction to the overheads (mentioned in a previous post) but does not put a limit on it. I've heard of .100 cuts but that sounds extreme. With a ratio of .0123" of of the manifold face per .010" off the combustion face, the manifold face (not real thick to begin with) gets too thin in a hurry. That means whacking it off the manifold itself to keep from stripping the threads for the manifold bolts, and so on.

[hchris6360]

The older heads don't have enough deck thickness to make a .100 cut, though the Stage VI heads can. I find that the block has the posibility of taking a .050 cut. At least on the RB blocks I have measured. But you have to watch this too as clearance stack up can get you into trouble. I would think .060 would be about the max to take and have a strong deck. This is on the head. Too big a cut can lead to intake manifold sealing problems. On my 440 I took .030 from the block and .020 from my heads (906) I then had the intake side of the head machined and didn't have to modify my intake manifold.

[dave571]

I found a car craft article titled "How to build abudget street machine: A low buck 360 powered duster"

They took .070 off of a set of 596 casting heads to get them down to 51cc.

Hughes did most of the work in the article.

I'd post a link, but I cant find it on line.

I have a hard copy of the article, only.

[dave571]

Wait, here's a link that may work

www.carcraft.com/projectbuild/1006/index.html

[ghenderson]

Milling 100 thow is not a problem as long as you consider your piston to head clearance. You will need min .060 for aluminum rod or .045 for steel rods. I have machined this much off 906 an452 heads on a number of occasions. The other thing to consider is that Chrysler cast iron heads are a very poor design by nature and were really never intended for true performance duty. You will run into detonation if you do not take care of a few issues no matter what the compression ratio due to a poorly configured combustion chamber. You will want to smooth out any sharp edges on the piston dome and you will want to unshroud the valves as much as you dare. The down side to raising the compression ratio on chryslers to much is that you will invaribly cause problems elsewere such as the main caps or through the main webbing in the bock. You are way better off keeping the compression ratio low and work the ports to find your horsepower. The motors that I have built with big compression and steel heads worked best on methanol. This virtually eliminates the detonation thing and makes for a very high torque motor. I am new to this forum and will try to answer questions when I can.