One morning, while traveling home from a local cars and coffee, the oil pressure gauge fell to zero and then the motor seized and stalled. Later inspection showed that a nylon shaft guide within the oil pump had split and fallen into the rotor, causing it to jam. The motor continued to try to turn the top of the pump shaft despite the jam at the bottom and this caused the shaft to twist upon itself and then snap.

The motor was removed, disassembled, and brought to a well-known Houston area machine shop for inspection and prep, Harold's Automotive Machine Shop. Unfortunately cracks were found in the block, likely from some freeze event decades ago. Time for a new BluePrint crate motor!

A replacement motor was ordered from BluePrint Engines, complete with aluminum intake manifold and cylinder heads, new distributor, carburetor, and water pump.

The motor was originally a 1982-1995 era 5.0 small block Windsor (302 cubic inches), allowing for a roller cam. BluePrint bored the block to 306 cubic inches and backdated it to run a carburetor and older style v-belt driven accessories. In this form the motor makes 375hp at 6,000rpm and 361lb-ft at 4,400rpm.

The install was a straight forward drop-in replacement of the old 289. The only slight modifications were replacing the straight Monte Carlo bar with a curved version to clear the new distributor, moving the wiring harness a little due to some of the gauge sender locations shifting, and buying a specialty set of v-belt pulleys from CVF Racing. These billet aluminum pulleys seemed to be the only ones that would work with the back-dated pump design.

One thing to note if you're doing a similar swap - the later 5.0 motors have a different firing order than the earlier small block Windsors. They also have a different imbalance, requiring a new 50oz. flexplate.

The motor started right up on the first try and ran smoothly with a completely steady needle on the vacuum gauge - a big difference from the worn old motor! Even with the extra power the motor seems perfectly able to maintain enough vacuum for the power brake booster. I definitely recommend BluePrint Engines!

With the motor out we also took the opportunity to upgrade the radiator to a larger 1967-1970 version originally intended for Mustangs with big block motors. Auto City Classics sells a nice all-aluminum radiator, and the inlet and outlet locations of the big block radiator line up with the small block motor, allowing for the use of standard sized 289 radiator hoses, assuming a standard 289 water pump (inlet and outlet both on passenger side).

This radiator still follows the flawed design of the early mustangs, where hot coolant flows directly down from the inlet to the outlet, underutilizing much of the radiator. Later mustangs switched to a cross-flow design with the inlet and outlet at opposite corners of the radiator, forcing hot coolant to better transverse the entire width of the cooling area. These cross-flow radiators require a water pump change to a unit with a driver's side inlet, and different hoses, so I stuck with the '67 big block design and it seems to be more than sufficient in the Texas heat.

To fit the larger radiator you'll need to remove a couple of inches of sheet metal from either side of the cowl around the radiator, a job easily done with a pneumatic nibbler. We then lined the opening with gasket intended for a barbeque smoker, and created mounting offsets by trimming sections of small aluminum pipe.