Minimum Cruise control vacuum?
 

Will a oem cruise control work with a raIV cam and 11 inches vacuum? Thinking of putting one on my 70 GTO. 400 ci.

I would put a long hose on a vacuum source and take the car for a drive and see what the vacuum is at light/medium load at 50-60-70 MPH. I assume that's the speeds you would most likely be using the cruise control at. The 11" you report I assume is at idle? If your cruising vacuum is 13 1/2 +" of vacuum, I tend to believe the cruise control system would work. I base this off the vacuum brake booster on my car. The brakes work just fine with 13 1/2" +.

Ok, thanks for input, thought someone may know if one could get cruise on a factory IV car or not an option.

Since your car won't be correct anyways why don't you get one of the new after market electron cruise controls? I have one and it works great.

If you use an older setup, just make sure the servo seals well. You're fine at 11" as long as it holds vacuum well. Mine was a early-mid 70's setup

70s devices are actually old now but in terms of quality they are very good, you can refer to poppy playtime chapter 3 to know more about 70s devices