GM 3.0 Liter 4 Cylinder Crossflow Engine Conversion


Well-known member
For over 25 years have been building the 3.0 liter crossflow engine for the series IIA and III.
The engine is based on the 151 cuin, 2.5 liter GM Iron Duke, but like hundreds of other engines it gains performance from a longer stroke.
The longer stroke provides 183 cuin, 3.0 Liters of swept volume.

Like the other GM inline engines of the period, this unit has metal timing gears, hydraulic lifters, and the core engines were built by the 100s of thousands.
The Iron Duke was used in AMC Jeeps, Pontiac cars, Chevy cars and trucks, vans, and is still used today in the Grumman LLV mail delivery trucks in USA and Canada.
This engine came in 2 versions:
the earlier GM 4 bolt pattern shared by 4 cylinders, inline 6 cylinders, the Vortec V6, and the famous Chevy 350 V8
the later inverted V pattern shared by the 2.8 Liter V6 and other later style metric engines.

These engines bolt in and the entire conversion can be completed in a weekend.
Here are pictures of one that was installed in a Defender 90.
Note the factory alternator and power steering brackets that make for an easy install.
Performance is about 140 HP.

This engine has the Weber 2 barrel carburetor, but it can also be fitted with the smaller Holley Sniper EFI.