As promised, here are some details for the Dodge 7/8" bore MC. This is what you get for about $60 bucks at O'Reilly Auto Parts. It is a MC for a 1995 Dodge Spirit with manual brakes (14" wheels). This particular model is brand new, made out of aluminum and has a plastic reservoir. These are all features that I like. Wilwood makes a nice 7'8" bore, direct bolt-in MC, but it has a reservoir lid that can only be taken off with an allen wrench. While it looks nice, I want to be able to check the fluid level without getting my tool box out.
This MC has two ports that have rather small fittings. The catalog description lists the outlet ports as being 3/8" inverted flair, but they sure seemed smaller.
The rear port of the MC is plumbed to the front brakes and nothing was needed to attache the line. The front port of the MC is plumbed to the rear line and required an adapter fitting that you can see in the picture. However, this adapter was too small for the fitting that was on my rear brake line, so what we decided to do was bend another line for the rear brakes. That way if I ever wanted to swap back to the other MC, it would be very simple to swap lines. We bent up a 5/16" line, using the old line as a template. It was fairly straight forward and simple.
The other issue with using this MC is that the mounting holes don't quite match the GM pattern. As you can see, we elected to notch the holes to make it easier.
The other issue with using this MC is that the pushrod hole is not as deep as the GM MC I was using, so the rod had to be shortened. The tip of the rod also had to be ground down slightly because the Dodge MC has a smaller diameter hole.
The bottom line is that this MC is a fairly easy swap into GM vehicles and is a viable OEM alternative to some of the aftermarket offerings. With a little ingenuity it can be made to work in applications that require a 7/8" bore MC.
The brakes feel very different now. The pedal feel is softer but I haven't really noticed a big increase in pedal travel. I am now easily able to lock up the brakes, when before I couldn't. Clearly the MC is generating more force at the caliper, which is what Ron was attempting to show with his spreadsheet.
A huge thanks to Ron Sutton for giving me the last needed nudge to make the swap to the 7/8" MC.
To wrap it up, here is a picture of the 275/35-18 BFG Rivals on the front.
There is mild rubbing on the sway bar at the extremes, but I don't see this as a huge issue. I may run a small spacer in the front if it become annoying, but for now I am going to work on a few other minor issues before the Holley LS Fest.
Andrew