[Cobra #3170]

If you are going period correct, why are you using 48IDA webbers instead of a single 4-barrel with center pivot floats or dual fours with side pivot floats?
I think Holman and Moody had several manifolds cast that used (4) 58 mm side draft Webbers but don't know of any that actually were installed on a production Cobra by Shelby.
I used 50 mm side drafts on a 1600cc Formula Atlantic engine that was less than 30 CI per cylinder. Seems like 48 mm might be a little small for 53 CI, the 289
factory 48 mm Webber set up was feeding 36 CI.