What made these special was the reworked combustion chambers, and the Alpina cam profile.
Cary's car has the correct stock Alpina carb setup.
I suppose they could work with solex or DCOE48's, but man...48's are HUGE. You know the diameter of the intake valves? 8) Neither are correct for when Alpina used these, but who knows what they did to sell them over the counter, remember their "distributors" were pretty much free to do whatever they wanted (and they still do)
My yellow E3 has 48's (we always called them 50's) and it just drowns until its wound up good, and thats with a big free-breathing 3.5 liter.
The literature from the tuner-shootout articles in the early 70's says Alpina used DCOE 40's.