If you don't mind, i would like to piggy back on this, since it seems to have been finished. I have basically the same problem. I have 1960 283, 230 h.p., stock,9.5:1,500 cfm. It was a motor that had not been opened up, and I had a shop rebuild it and give it back complete. Run the car 4500 miles, and kept having the top half of the plugs dark ( black in color but not built up). Wound up pulling a head, and 3 chambers were caked full of crud. The cylinders had vertical lines about 3/8 apart wher the rings rode, but not in between. Crank was scored, cam gone, etc. Did a another rebuild with different shop. Running .0025 piston clearence, everything else new. Hone job looked good. I had them put the pistons in (Cast Iron Rings), and I did the rest. I now have about 2500 miles on it, and I am getting I assume blowby from the rings since rebuild. Heads have new guides and seats, and rebuilt twice. Does not smoke at start up, but will if I lug it backing up or starting out. I have a road draft tube, but it will push oil out the Oil Filler neck which has a breather in it. I tried a pcv instead of the road draft, but did not help. I started it using detergent oil with some GM rebuild juice because of the cam. I'm about at my whits end, and I really don't care to pull that thing out again. This is not a race motor, but I drive it, not baby it. It usually doesn't run above 3500. Any help or suggestions would be greatly appreciated.
