Manifold Clearance Problems
Recently it was brought to my attention that on some 1500cc Spitfires and Midgets there is a clearance problem between the bottom of the intake manifold and the exhaust manifold. If your car has this problem it will have a massive vacuum leak and exhibit the symptom of immediately dying upon startup. Some solutions are creating clearance between the manifolds by grinding or replacing the exhaust manifold with an aftermarket header.