Based on posts from another site from the past on the same topic...I think what CAB meant was it picked-up 30 using the 2x4500 on the TR. FWIW unless your CFE TR is wildly engineered for a different application AND the tune/curve is off, it's unlikely THAT cast single 4 is going to pick up the performance. NOW a 420 'done right' with a good carb using Q16 might be as good as the current CFE with 2 'inlets'. As for the single 4 conversion to the CFE...It's been my experience that by the time a teepee top that minimizes distribution issues is made, the plenum will be too big!