I've got the low performance version in my car.
I'm wondering if anyone has done the old-school approach with this engine by swapping rocker arm/ratio; camshaft profiles; shaved cylinder heads; that sort of thing?
What'* available for this engine during a rebuild?

they make a low performance one? j/k man yeah youve got the series 1. but i always thought they did pretty good.never driven one. but i loves my series 2.

Dr Jay is in the process with a Series 1 L67 right now. Many of his ideas would work for you. Check in performance, it'* about 8 or 9 pages long now. The whole saga.