Hey dudes! I was just out at the pick and pull today and was walking out and looked at a datsun- 240, 1974 year to be exact. Well guess what, the brake master cylinder is the dual circut type and 7/8 bore,-same as the one that they put on the 68 122s. Virtical bolt pattern too at 2.25 inches. It even comes with and adapter plate on the car if you want to mount horizontally. The lines exit downward though and not to the left (as the original one does). The wilwood unit exits downward like the datsun cylinder. I just paid $120 for a wilwood unit and they only offer a 1" bore. The volvo cylinder uses a little retaining plate to keep the rod from falling out and I dont think this will be a problem with the datsun piece since it has the same bore size, if you have taken one apart you know what I mean. Check to be sure though. Just thought Id pass this along to those who have or want to convert to the dual circut brake system. You will have to make new brake lines and its pretty tight with the steering column right below it but its doable, or you can use fexible brake lines with the proper adapters, speedwaymotors.com has a good selection.