Manifold height?

I have the Air-Gap on my 360 which is an excellent intake. The gap will increase warm up time much like a big block needs time to warm up. So, when it gets cooler outside, chilly like, and the car needs a minor warm up time, add 5 min.'s to it with the air gap on.
That's it.

Just use with a cam in it's RPM range. It is fine on a stock 340 due to the cams normal RPM range.