design - Land Rover section





From Teriann: Up until 2009 the hardest part of engineering an engine/gearbox swap into a Series Land Rover was connecting the gearbox to the transfercase.  Individual fabricators solved this by engineering an adapter and having one to a few machined for that particular conversion.  The adapters were expensive. some not so robust, some quite good, but all very hard to come by if you were not in line when a fabricator had adapters machined.  Usually your conversion choices were limited by the adapter you could find.  Advance Adapters completely changed the playing field by offering off the shelf adapters that allow the robust Series transfercases to be mated to common American light truck gearboxes, both 4 and 5 speed.  Suddenly your conversion choices are greatly expanded, the engineering requirements for the conversion are simplified and you are not paying for a custom adapter to be specially machined.  With Land Rover discontinuing Series engine and gearbox parts and aftermarket sources reluctant to fill in the gaps with high quality parts, engine/gearbox swaps will become increasingly important over time for people who put a lot of miles on their Series Land Rovers.  I personally feel that these adapters  are important enough to the future of Series Land Rover conversions that I am willing to give Advance Adapters this page in my web site to advertise their Series transfercase adapters.

NOTE: Information on this page and pictures were supplied by Matthew Jackson at Advanced Adapters.  For additional information about using these adapters please contact Matthew Jackson directly at 1-800-350-2223, EXT 523


Advance Adapters has been in the 4 wheel drive conversion market since 1971. Unfortunately for the Series Land Rover owner little in the way of adapters has been made available. For many years adapting different engines and transmissions has been a hassle to say the least. Recently Advance Adapters has developed an adapter  for land Rover transfercases that is easily installed onto the transfer case and can readily be used directly to a number of other brand transmission tail housings. Or with one of Advance Adapters “Dana 300/New process 23 spline “ circular six bolt pattern.


Advance Adapter
Isometric Drawing

NP435 with Advance Adapter
New Process 435 with Dana 300 adapter, part number 50-3801


The Series Land Rover adapter features dual sealed ball bearings and a seal. The common problem of fluid transfer from one case to the other is a none issue. In fact most of the adapters and tail housings feature an additional seal.

GM 10 spline SM465 adapter part number 50-9002



Another feature is the ability to adjust the angle of the transfer case. Known as ”clocking”. This allows you to maximize bell housing, drive shaft and chassis clearance.  An additional feature is built in vent passage and barbed fitting for a hose. The transfer case originally vented into the main transmission.

Clocking feature
Clocking” feature

Mock up prototype
Mock up for prototype


The manufacturing of the new “spud “shaft is done right here in Paso Robles, California. The steel is an 8620 alloy. A special cutter for the Land Rover spline was custom manufactured especially for us.

Hobbing the shaft

Final product prior to heat treat

The Series Land Rover adapter is offered for several applications. A GM 10 spline, a 23 spline and a 29 spline. The transmissions that work with this adapter are as follows:

GM 4wd 1970-1979 10 spline SM465 with Series transfercase and Advance adapters
part numbers 50-9002 and 51-9807

NV3550, use  part number 50-9000

NV 4500 use  part number 50-9000 for 23 spline and 50-9001 for 29 spline

The 23 spline , as stated above, uses either a stock tail housing or one of Advance Adapters Dana 300/New process 23 spline “ style of adapter.

The NV4500 series of transmissions after 1995 share a common gear set and case. Therefore , making the NV4500 interchangeable among the various versions. Input shafts can be Chevrolet 10 spline, Dodge 1 1/8th 10 spline and Dodge 1 ¼ 10 spline. Output shafts can be Chevrolet 32 spline, Dodge 23/29 spline. The 29 spline is a commonly available HD unit. For example, if a person came up with a Chevrolet NV4500 transmission. They would simply have to change the rear output shaft and Factory tail housing to a Dodge style.


Here are some pictures of a Chevy NP435 gearbox with a Series transfercase installed in a Land Rover model 88:

This set up required two adapters, 50-3801 and Land Rover adapter 50-9000

NP435 installed in Land Rover
The cross member was modified with tabs and Advance Adapters part number 716008 mount to fit the Series frame. The top right picture on this page provides a view of the 716008 adapter installed.  The Adapter's mount is used to support the gearbox and transfercase. The clutch linkage is also available through Advance Adapters.  The two adapters add 6 inches to the total length of the gearbox and transfercase length. 

  Land Rover drivetrain

Drivetrain shown above after over a year of hard off road use.
Rugged and leak free.


The castings are manufactured with a heat treated alloy known as 356-t6. All versions of the Series Land Rover transfer case adapter (50-9000, 50-9001 and 50-9002) share the same casting, seal and bearings. Further increasing adaptability. If a person wanted to change from a “Granny” 4 speed transmission to a NV 4500. A simple “spud” shaft swap is all that would be required.

Advanced Adapters castings
Castings on shelf, ready to ship

Land Rover transfercase
Rebuilt Series Land Rover transfer case and a
50-9000 adapter.


Installing a stronger American truck top loader gearbox into a Series Land Rover:

The stock Series Land Rover gearbox is good for only about 120 HP and about 160 lbft of torque.  So it is not of much use in an engine swap.  The picture to the left shows a Land Rover first gear next to a SM465 first gear. 

The good news is that unlike the weak Series gearbox, the Series transfercase is one of the strongest in its class and the strongest stock transfercase with both front and rear outputs lined up on the right side.  So a US light truck top loader gearbox coupled to a Series transfercase though Advance Adapters adapter is a strong reliable solution to most engine swaps.

Land Rover gear


A U.S. light truck top loader gearbox is wider and deeper than a Series gearbox.

Land Rover gearbox top Land Rover gearbox side

A Series Land Rover gearbox in comparison with a SM465 gearbox with Chevy bellhousing and 51-9807 adapter

When swapping a V8 or V6 into a Series Land Rover you should center the engine as much as possible and still fit the mechanical brake linkage. The firewall opening for the bellhousing will have to be cut taller (usually about 1 inch to 2 inches and wider, usually by about 4 to 5 inches wider on the right side).  This means you will need to fabricate a new gearbox tunnel cover and cut down the width of the right side floorboard. The stock Land Rover steering box will be in the way of the V engine so this is a good time to convert to power steering.

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© 1997, 2001 TeriAnn Wakeman. All rights reserved.