We wanted to know the exact compression ratio of our combination, as well as equalize the volume on all eight chambers. We shelled out for a graduated burette and clamp from Chem Lab Supplies-a bargain at less than $50-while the stand was expertly crafted from some junk we had laying around. A 5-inch square of 11/44-inch Plexiglas was a freebie at our local glass shop, and was drilled and countersunk to make the CCing fixture. The hole must be drilled so it can be set to an edge, and the head slightly tilted to avoid air bubbles. Seal the fixture with white grease on the deck and fill 'er up, reading the volume. Isopropyl alcohol was used as the checking fluid. Our radically modified, closed-chamber 915s checked out at 85cc, or only one cc less than a stock open chamber. However, we had quench.