th 400 speedo

[jimz 509]

SO im running a th 400 behind my lt l have been using the front wheel speed sensor as a reference for the speedo,which was ok,for the track,but really lacks low speed resolution,has anyone done the math to use the abs tone ring for this?and could you share please?

[ScottP]

Another option that I've used when retrofitting a TH400 behind an LT1 (or any GM ECM/PCM that needs
a VSS input) is to retrofit the 40 tooth reluctor and VSS sensor onto the TH400. It only requires the
following two parts:

Reluctor wheel – GM p/n 8655315
Speed sensor – GM p/n 8655291

Heat up the wheel in the oven, and it'll slip onto the TH400 output shaft. The new VSS goes where
the old speedo cable drive was located.

Good luck whatever way you happen to go.

-Scott

[jimz 509]

hey thanks for that it would for sure be the easiest, i didnt realize!!