1st, great to hear the IMP is back on the front of the stove. Always admired that car.

2nd, I an curious why you aren't going with a stroker. The numbers you listed are healthy, but if I were to build a fresh engine with a decent budget, it would have a few more cubes and a taller gear to keep the RPMs down. 40-50 year old rotating assembly parts?

3rd, I love the TQ sound too and the 'coasting on primaries' deal. I'd really look into a dry intake with low height and long tubes to tune for the same RPM as the rest of the build (under 4500) you have talked about machine shop and fabrication equipment before. I'd imagine that you could come up with a small/huge throttle body and the intake to head plates. The tubing would be the part that would require a bunch more effort, but would result in something special. Also, having 2 TPS inputs to map properly would take a bit of time. If you use the TQ, my main concern is all the stuff that is in gas these days. Will the body hold up to warm temps (I assume you aren't going to run a 160 tstat) and the various oxygenates and other junk in current gas?

4th, Is this going to be NA? I appreciate the E heads being new and lighter. Will they be a bit much for a stock size, low RPM engine? The cam seems fairly mild, which means fairly high static compression plus mild duration, so the quench better be dialed in for optimum timing without pre-ignition.