Here’s a 2013 article from the Stromberg website that I wish I’d seen earlier, I can 100% confirm the accuracy of the findings!
Will take the advice in the article in terms of the K&N element and see how it goes
From the article –
Our buddy Lez dug into his legendary vintage magazine stash for this great Street Rodder magazine tech article all about choosing the best air filters for your Stromberg 97s. Written by the highly esteemed Ron Ceridono back in 1998, with input from Stromberg expert Jere Jobe (from Vintage Carburetion North), it is, of course, just as relevant today as then. Sorry about the quality. It’s a scan of a photocopy, but if you click on the pages below, they will come up at a readable size.
While it’s well worth reading every word – hey we’ve even thrown in a free Dick Spadaro ad – if you’re looking for the ‘executive summary’, it’s this….. “if you have an air filter on your 97, make sure it’s a K&N E-3120”. Here’s why: Click the pages below to view, or ‘right-click’ this link to download the 2-page pdf. Choosing The Right Air Filter