Mark Houlahan
Brand Manager, Mustang Monthly
April 1, 2002
Photos By: Steve Turner, Chuck James
Our Probe 331 is gently laid into its new home with the aid of the new billet CNC-steel 5.0 EFI engine lift plate from Summit Racing. This is a trick piece in that it bolts to all current EFI lower manifolds including Holley (which we're using here), Trick Flow, Edelbrock, Ford, and more.

Horse Sense: While the 347 stroker has been wildly popular in the past, the 331-stroked variant of the Ford small-block is gaining in popularity. The 331's ability to make more rpm is one of its nicer features. The Probe 331 is created when a 3.250-inch crank stroke is matched up with 5.400-inch-long connecting rods and 4.030-inch forged Probe pistons. The 347 differs by using a 3.400-inch crank stroke with 5.315-inch-long rods and the same 4.030-inch forged Probe pistons.

A few issues back ("Just Right," Nov. '01, p. 37), our left-coast editor Tom Wilson followed along at the Probe Racing Components shop as its technicians screwed together a spanking-new 331 stroker for Editor Turner's purple coupe. The Mustang's aging 5.0 (a 306, actually) had been a test mule installed about six years and three transmissions ago. It was time for the engine to retire-which it did on the side of the road one day when a head gasket decided it didn't want to seal anymore.

The new Probe 331 arrived beautifully crated and ready for installation, save for a few valvetrain items and a new clutch. After uncrating the engine and setting it up on an engine stand, we stood there with notepads, keeping track of all the fittings, hoses, and so on that would be needed to install a fresh engine-a crate engine, if you will.

Thus, a story was born: Installing the 331 and noting the problems that creep up during a crate-engine installation. Of course, some things will differ (we changed intakes, and thus needed different lengths of vacuum line) from your crate-motor install, but it will nonetheless get you thinking ahead of time for all the little things that frustrate and prolong the process.