Mike, you can almost realize as much of a performance improvement by simple alignment of your stock intakes as to the heat spacers, and the aluminum barrels aligned to the ports on your head. There is is an incredible amount of slop in our intakes as built and installed. With your carbs off and the manifolds bolted to the head, feel with your finger the uneven and shoved over to one side, the 90 degree steps the fuel/air flows encounters in just that short of a span. I bolted up both mans. and spacers, sans carbs, aligned as good as I could get by feel, locked them down in place and used a Shepard hook scribe to mark where a little filing with a 5/16th rat tail file and a finish with sandpaper to blend them in. My final step was to drill for 1/8th" dowel pins (2 each) to keep the sweet spots in place for the next teardown/reassemble. And I used a gram scale to make sure I was reasonably close in the amount of material I removed from each segment, I have no idea if weighing accomplished diddly-doo, but I did it anyway. The center to center on the bolted up and pinned in manis came out 3/32nd" tighter than my carbs c to c, so was no issue there. All in all, I do notice a smoother power delivery at all RPMs, even at idle. Greater velocity means more fuel will enter the combust. chamber and that's the goal. So, yeah, billet intakes would/should be superior to OEM as installed. At least one should hope so.
