Tech notes
LS swap and mechanical speedometer guides
Build write-ups and fitment guides: the stuff we end up explaining on the phone twice a week. Start with keeping your factory speedometer behind a 4L60E or 4L80E.
Start here · Fitment guide
How to keep your mechanical speedometer with an LS swap and a 4L60E or 4L80E
Your LS and electronic overdrive don't have to cost you the original gauge cluster. Here's how a mechanical drive puts the cable back on the transmission.
8 min read
All articles
Comparison
4L60E vs 4L80E for an LS swap: which one should you run?
Torque ratings, gear ratios, weight, length and the parts that change with each one, so you buy the right transmission the first time.
9 min read
Tech explainer
Why modern GM transmissions have no speedometer cable, and your options
The vehicle speed sensor replaced the cable for a reason. Here's what it does, and three ways to get a working speedometer in an older car.
7 min read
Build
Building a sleeper: stock-looking hot rod, modern LS power
The best sleepers give nothing away from the driver's seat. Here's where LS swaps usually blow the cover, and how to keep it.
7 min read
Fitment guide
Which transmission goes with an LS1, LS2, LS3, LS7 or LS9?
Factory torque, the transmission each engine came with, and where a 4L60E-family or 4L80E fits in a swap.
8 min read
Fitment guide
Speedometer gear calculation for an LS swap: the formula, worked out
Tire diameter and rear gear in, drive and driven tooth count out. The math behind the calculator, with an example you can check by hand.
6 min read