Boss Hog 48400 Night Stalker Torque Converter | GM 700R4/200R | Stock Stall | Lock-Up | 27 Spline

The Boss Hog 48400 Night Stalker Series Torque Converter is a stock replacement unit for GM 700R4 and 200R transmissions using LT-type engines with a 3-step, 27-spline input shaft. Built to original factory stall specifications, this lock-up converter delivers reliable OEM-style performance with no added stall — ideal for daily drivers and stock rebuilds.

Precision-built with a 12" factory core, this converter includes Torrington-style incased bearings, a heavy-duty stator, and a high-temp O-ring for long-lasting reliability. Digitally balanced and leak-tested in the USA.

Upgrade Tip: For builds with upgraded intake, exhaust, cam, or gearing, consider moving up to the Street Bandit Series. For power adder setups, choose the Outlaw Series.

Key Features

• Stock stall range – no additional stall added

• Lock-up compatible

• Fits GM 700R4 and 200R transmissions (LT-type, 3-step input shaft)

• 12" factory-size core

• 10.75" bolt circle

• 27 spline input shaft (count the smaller splines)

• 1.703" crank pilot

• Bolt size: 10mm x 1.5 pitch

• Torrington-style incased bearings

• Modified heavy-duty stator

• Extreme-duty lock-up

• Extreme temp heavy-duty O-ring

• No anti-balloon plate

• Fins are 4-corner tack welded or furnace-brazed

• Leak and pressure tested

• Digitally balanced

• Steel construction, black painted finish

• Made in the USA

• Sold individually

Vehicle Fitment

• GM vehicles with 700R4 or 200R automatic transmissions

• LT-type engine setups using a 3-step, 27-spline input shaft

• Intended for stock replacement and daily driver applications

What’s Included

• 1x Boss Hog 48400 Night Stalker Lock-Up Torque Converter

Installation Tips

• Use Type F transmission fluid

• Install an auxiliary transmission cooler

• Apply blue Loctite on all converter bolts