I have a 77 FJ40 that has a DIU HEI Distributor that I didn't install. The engine runs, but not at full power. When I check the timing, the 7 degree BTDC ball appears to be retarded by around 15 degrees, with vacuum plugged running at 650 RPM. When I attach the vacuum line the pointer and ball still look about 8 degrees retarded. The problem I'm having is that I can't turn the distributor CCW any further as the vacuum diaphram assembly gets stopped by the oil filter. I'm trying to find out if it's possible that the distributor was installed incorrectly where the gear was off by a tooth or two? What's involved to correct this issue? where can I find a link to the installation instructions? Thanks.