These high quality machined aluminum velocity stacks are designed specifically to fit 1.75 SU and Zenith-Stromberg carburetors on many Triumph and MG engines. They'll also fit the Hitachi clone of the SU (HS6 and H6), which are found on some Datsun engines.
Dyno tests have shown an amazing increase of 4-6 horsepower on four cylinder Triumph engines, and up to an 8 horsepower increase on the Triumph GT-6. Sold individually.
For a low-profile, free-flowing air filter we recommend our Custom Air Filter for 5" Velocity Stacks, Part No. 3894-127 (sold separately).