Magnum Head Milling

[bobscuda67]

I built my motor with dish pistons and I will use truck magnum heads. Everything I read stated that magnum heads were in the 61-63 cc range. So now I have one good #466 casting and of course it cc'd out at 67 cc's. Now I have I have to loose around 10cc's to get the compression up. Question is, how far can you mill a magnum head and how much per cc? Thanks, Bob

 

[Brambles]

OH great now you have me thinking too.

I built a magnum headed LA 360 a couple years ago and when I was doing my compression calculations I think I was using 62 cc's for my compression ratio but don't remember if I acutally measured them?????? So my 9.45:1 might be closer to 8.9:1 if I got a bad set of heads. Guess I'll tear my motor down and see if I have to do some milling and maybe install some flat valves to get the compression up.

 

[bobscuda67]

You can't take posted numbers as gospel. I used a syringe to cc my heads that I had for a few years and it looks like ths rubber plunger is a little swollen. I bought a graduated cylinder to measure it with and I'm hoping that with a more accurate measurement I can loose a few cc's. Still have not found out how much to mill a magnum head for one cc. Bob

 

[Brambles]

No sweat, I'm still going to rip my motor apart. My compression seem a little low at 150 psi.