Long story short, I need something fixed on my heads for the 305 so they are coming off and going to a machine shop once I find one down here. I am switching to a Fel Pro #1094 .015 gasket anyhow.

These are rebuilt 601 castings, 58 cc. Fully ported with larger, 1.94 intake valves and a 3 angle valve job. These heads are staying with this motor for the remainder of it's life since I am probably going with Vortecs when I build a 350 (probably the year 2028)

They are on a 84 LG4 block .060 overbore (315) with cast dished pistons. I thought since they will be off, I am going to see about getting them milled. I think right now this engine has like a very low 8:6 comp ratio. This is what I have been told/read on LG4s.

I was wondering if anyone knows how much or how to calculate how much I should take off to bring it up to a 10:0-10:1 ratio? I don't want to sound like an idiot when I talk to the machine shop.

As a comparism, I think in that old Car Craft 305 build up, they took those Vortec heads down to 55cc to get a 10:0 comp ratio using the 1094 gasket. So I would ask them to mill them down to .030 to bring it to 55cc?

I know the intake needs milled too if I go with flat milling. This will be great since the rear of my intake is warped a little where it seals to the block.

I know this isn't much but it will probably give a nice seat of the pants improvement when I get it all back together.

Thanks in advance for any suggestions.

 

I believe the rule of thumb for milling heads is .00625 per cc.

 

Yeah it will depend on the heads. On my Brodix Street heads it was .006" per CC which is very close to the above quote by Tibo. Allen