After reading countless threads on The Mini Forum and articles throughout the internet about Webers on Mini’s, I read more and more that the amount the Weber can breath, the length of the manifold and the length of the ram pipes matter most.
I’ve already had my thoughts on my inlet manifold as you can read here, and since that I’ve bought a 3.75 inch manifold from Minispares Centre which fits perfect. I also already have fairly long ram pipes which I am happy with, but after cutting my bulkhead out to make the Weber "fit", I thought the breathing space could be improved if I cut slightly more away, if that was possible.
After a few measurements of the space behind the speedo (I’m still going keep my 3-clock centre binnacle speedo set-up), it was possible. So here’s a photo, before I made the modifications:
As you can see, its a very tight fit. Not much room for any air to get in there.
And then above, I’ve made the area around it slightly bigger as you can see.
The modifications to the bulkhead at the moment are pretty rough and tatty, but I’ll clean it all up a lot after I’ve got my engine removed. Hopefully this space I’ve created, along with more space after cleaning it up when the engine is out, will be enough for the Weber to breath and flow well. Check the comments on this post for any updates.


Maybe, you can try with something like this Bulkhead Box from AvonBar:
https://www.speedgenie.co.uk/a... will work better for sure
Yeah, I’ve noticed the AvonBar Weber boxes before – they are awesome. Although again for saving money and time I am not going to bother. If I am pleased with the Weber after this rebuild, at next rebuild I’ll probably strip the shell bear and install one!
Any room for an air filter with the ram pipes inside if you use Specialist Components’ 20mm ram pipes: specialist-components.co.uk/cn... ? I’m planning on doing something like this with mine.