I am converting my 69 to disc up front. I will remove the stock distribution block. I want to install the proportioning valve near that location. But there are no existing holes suitable (remember the 69 used a metering valve under the master and never used a prop valve even for the optional disc brakes). For those that have done this before, do I drill holes and tap them out? Can I hold the valve with only one bolt? It seems real difficult to get a drill in there to make a hole, let alone tap it, unless I move the new prop valve to bottom of the frame rail at the bend. But then all the lines to the existing distribution block will be too short. Your experiences please.

What we did on our 69 was use all 71 Chevelle parts, master cylinder, booster, and proporting valve. The valve lined up where it wanted to live on the frame so we drilled it out and put two self threaded bolts in it just like the factory used and had no problems. In fact my headers (Dynomax) clear the valve with room to spare. 71 to 77 Chevelles used the same valve unless you want a new one, it was under $60 when I bought mine four years ago.