Dave, you're correct 1380 is the weight for those with hugh 2.0 motors, but you also need to add 40 lbs to that for the modified tub.
Per section 18.1 ....
"All series of Lotus 7, 7A, Super 7, and their clone or kit
forms such as Birkin, Westfield, Locost, are automatically
classified as modified tubs. This also applies to the Cobra
and its clones."
That pushes you up to 1420 as the minimum weight, so you only need to shave off 40 pounds. Get on one of your bikes and do some of those mountains!!! Just kidding!
Your other option is to put an 1800cc motor in and your minimum goes down by 100 lbs. and you'll have to add weight. With my 1800 K series, my car comes in at 1164, so its a good thing I carry all this extra weight.
Tom