Choosing Your PTO

The Power Take Off flange (PTO)is a 1" thick disc that bolts to the rear of the crankshaft; it is what allows the driveshaft to be bolted to the back of the engine.

PTOs are made to fit specific engines and match the engine's crankshaft bolt pattern. Engines range from the newer Chevy LS platform to Small Block Chevys in both two-piece and-one piece rear main seals, plus Big Block PTOs for Ford, Chevy and Oldmobiles as well as others.

1.   Here we see some of the many PTOs that are available.

2.   PTOs are made in two basic styles: one that fits with a flexplate, and another that works with a flywheel. The PTO on the left fits with a flexplate installation (note the recess designed to fit over the crank that sticks past the flexplate). The PTO on the right fits a flywheel and has a register that will center into the flywheel.

Beyond that, there are also 2 different driveshaft bolt patterns: one being the 1310 pattern, and the other the 1350 pattern.

3.  The 1310 bolt pattern is 2" x 2 ⅜" and uses a ⅜" bolt for the driveshaft mounting.

4.   The 1350 bolt pattern, on the other hand, has a 2 ⅜" x 2 ⅞" bolt pattern and uses a ⁷⁄₁₆" bolt for the driveshaft attachment.

5.   The PTO on the left is a 1350 version with the larger bolt pattern, and on the right we see a PTO with the smaller 1310 bolt pattern.