Meanwhile these similar parts were offered on eBay by a seller named "turner.carbs" (Andrew Turner) for £49.95/set (plus shipping). They feature "a 7 degree exponential full flare" and are 13mm deep. The small notches at the edges are likely intended to clear the wider spaced posts in the MGB air filter housings. This may require a bit of fettling to make them fit in the MGA air cleaners. Increased thickness is not good inside of a shallow side entry air cleaner, although there is so far no basis for comparison.

This one is offered by Rimmer Brothers (Part number 01FD23ALO1). They measure 16mm thick, and 100mm diameter. Despite being aluminum they are surprisingly weighty. Having seen this picture, I'm inclined to believe the 7 degree angle may refer to the ramp angle inboard from the top ridge, as the outer ramp appears to be much steeper. The rim at the base is 3mm thick. This part may work okay inside of the deeper MGB filter housings. For the shallower Volkes filters on MGA this part may work better if you shave the back side to reduce the thickness to about 8-mm (5/16-in). That may lose about 2/3 of the weight in the process. The extra thickness is obviously a hindrance. There is likely little or no benefit in the length of the cylindrical throat. Smaller OD and slight difference in ramp angle may be nearly insignificant. A final sharp edge on the OD may be a good thing.


On 10/5/2018, Thomas Aczel wrote:
"I had them machined down, .... sent you a photo of the modified stub stacks fitted when looking at my car". -- Regards, Tom