Re: help with 83 258 intake manifold
I did the same thing when I added fuel injection. My old manifold was a one-barrel (EFI required 2-barrel) and the exhaust didn't have an O2 sensor provision. I removed the EGR (original intake didn't have it) and covered the hole with an aluminum plate and a gasket. I cut the tube from the exhaust, crimped it shut, and sealed the crimp with a brazing rod. I don't know what the flow for the coolant is and don't think it matters. Just rerouted my heater lines. That #4 is a knock sensor and I'm not sure about the others. For all of those that I didn't use for the EFI I just removed them and filled the holes with 3/8 NPT brass pipe plugs with some teflon on them. My heating element is not currently hooked up as the jeep doesn't get driven much in the winter.
'75 CJ5,258 w/Howell EFI,T18a,4.27's,33's,On-board air,Warn 8274