Monthly Archives: November 2026

SMALL BLOCK CHEVY ENGINES… When did they change the Small Block Chevy Engine? The Chevy engine went through many changes over the years, the first change was in 1980: Engines 1979 and earlier had a port side dipstick on I/O engines. From 1980 to 1985, the engine had a starboard side dipstick on I/O engine. […]

Engine Alignment Inboard…   How do I align my Inboard Engine? Important: Engine alignment MUST BE RECHECKED with boat in the water, fuel tanks filled and with a normal load on board. Engine must be aligned so that transmission and propeller shaft coupling center-lines are aligned and coupling faces are parallel within .003″ (0.07 mm). […]

National Pipe Threads (NPT) Explained Male threads:Measure the outside diameter of the large portion of the thread at “A“; Find figure nearest this dimension in column 1 or 2 of chart. The dimension in column 3 will be your nominal pipe thread size. Female Threads:Measure top diameter of thread at “B“; Find figure nearest this […]

Transmission General Information: All 1017 and 1018 Velvet Drive Reduction units use a 5 inch coupling. You can easily replace a 1017 with a 1018 but it is 7/8 of an inch longer. Make sure you can move your propeller shaft coupling back 7/8 of an inch to be able to use the much heavier […]

What Model or Ratio Velvet Drive do I Have? Transmission Assembly Number Previous Trans. Assembly Number Transmission Ratio Forward Reverse 10-17-000-001 AS1-71C 1:1 1:1 10-17-000-002 AS1-71CR 1:1 1:1 10-17-000-003 AS1-71CBR 1:1 1:1 10-17-000-004 AS1·:71CBR 1:1 1:1 10-17-000-005 AS2-71C 1.52:1 1.52:1 10-17-000-006 AS2-71CR 1.52:1 1.52:1 10-17-000-007 AS7-71C 1.91:1 1.91:1 10-17-000-008 AS7-71CR 1.91:1 1.91:1 10-17-000-009 AS3-71C 2.10:1 […]

Paragon Transmissions…   How do I know which model number is in which series of Paragon Transmissions?   The Paragon marine transmission and its parts can be very confusing.  The Paragon “P” series marine transmission with its myriad of model numbers is really simple to understand.  They made basically 3 models of these transmissions.  The […]

Velvet Drive Pump Indexing: How do I index the pump on my Velvet Drive transmission? The Velvet Drive marine transmission is probably the most common transmission ever produced. They have several models. They use model numbers like 71, 72, 1017, 1018, 1004, 1005, 1013, 1014. These models all use a cast iron case and have […]