Vintage design Austin Healey 100-4 BN1 BN2 distributor vacuum. Concours quality. These units are built from the original Lucas components and have upgraded internal diaphragm for improved performance. Each Lucas unit is correctly stamped with the original part number and include the correct threaded vacuum line fitting. Important there are two options available and you must determine which unit you require. Early Lucas distributor 40320 uses vacuum 420006. The later Lucas distributors 40495 use vacuum 421943 . Both of these vacuum units have a pin link.Important select the appropriate option above. Please check your distributor number to determine which option / vacuum you require. If you are rebuilding a 100-4 LeMans Lucas distributor see the LeMans section in our parts listing for correct vacuum units.