700R4: B&M Tork Master 2000

The B&M 70420 Tork Master 2000—the final link for the 700R4 swap.

With the 1992 700R4 ready and the newly rebuilt 250 Inline 6 back home, I needed a torque converter to marry the two together. I went with the B&M 70420 Tork Master 2000.

A torque converter is essentially a fluid coupling that allows the engine to spin somewhat independently of the transmission. For this build, the Tork Master 2000 is ideal because it offers a stall speed of 1900–2100 RPM. This is slightly higher than a stock converter, meaning the engine can rev a little higher into its torque curve before the car starts moving. For a turbocharged Inline 6, this helps the turbo begin to spool just a bit earlier when pulling away from a light, but it stays tight enough to keep the “daily driver” manners intact.

Pre-filling the converter with fresh ATF to protect the internals on the first start.

Before installation, I filled the converter with fluid as suggested. Dry starts are the fastest way to kill a new converter.

Seated deep in the 700R4. You have to hear three distinct “clicks” to know it’s fully on the splines.

The most critical part of this install is making sure the converter is fully seated on the 700R4 splines. If it’s not all the way in, you’ll destroy the transmission pump the second you bolt the bellhousing to the engine. I made sure it was seated deep before buttoning everything up to the 250’s flexplate.