In talking to Keith's chief engine builder they do not use a torque wrench on the intake manifolds of the FEs they build. The "snug to feel" incrementally as they go around the intake in the proper sequence. They have found that with the aluminum heads that the intake bolts are prone to pulling out the threads in the heads if you torque to specs without developing a "feel" for what you're doing. I used the same methodology on mine and it worked fine. I've re-snugged a half dozen times since the intake went on with zero
oil, water or vacuum leaks.