I bought my manifold from TWM (The Weber Man) back in 1988 - at the time, it was based in Goleta and doing Weber installations for US customers. My Webers do fit with the stock cross bar, where I have the smallest of "relief" in one of the velocity stacks. Note though that I believe I had the last manifold made with that mold before it was lost. There was a group of Alpine owners who had to commission TWM to make a whole new one after me. So there is no telling if the later TWM manifolds are the same.
HOWEVER, (1) even though it fits, that does not allow for an air cleaner, and (2) I'm now running longer velocity stacks and they definitely would have hit it.
I took off my cross bar when I decided air cleaners were more important than cool looking stacks on a car that is regularly driven. FWIW, I'm running UNI air cleaner foam covers that go on each stack.
OK, but here's the thing. I did a lot of research back then. I don't know where I found it. But I found a write up that did not have to do with Webers. It was a story about the history of the Alpine. The car was NOT designed to have these crossbars. Those were not added until pre-production when there was some shuttle shaking in the car - not because of cracking or anything else. One would therefore conclude, as I did, that if the bars are removed and there is no shaking, there is no reason to keep them. Again, remember, the car was not designed to have them to begin with, it was just an afterthought band-aid. Well, I can tell you that I get no shuttle shake at all. So I suspect whatever they thought they had, it wasn't caused by the lack of the braces.
Note, I have had shuttle shake. It has always been remedied by new tires, balanced wheels or wire wheels needing to be trued. Otherwise, in the 30 years I've been running without the bar, I've had no issue. Rootes got misdirected somehow.
Here is another point to consider. My father was an engineer, a real rocket scientist actually. He pointed out that for a brace to work, it needs to be straight. Any curve or bend will pretty much eliminate the structural benefit. Did he do a full analysis? No. Could a bent or curved rod provide something more than nothing? Maybe. But since I have no problem, I see no reason to bother with a marginal idea.
