Page 3

Engine Disassembly
One of the cost saving benefits of doing a stroker motor was the fact we'd use our old block as the foundation. The '89 5.0L block has never been bored over, and since we had been racing it for the past two years, we were certain there were no cracks or surprises.

We spent a weekend pulling and disassembling the old engine. In order to prevent interference with the rod bolts we clearanced the bottom of the cylinder bores- a common procedure for 302 based strokers. Finally we took a few measurements and dropped the motor off at the machine shop with our specifications.

1. It's hard to believe, but our "400 Horse 302" project is tired and ready to receive an overhaul.

2. With the engine bay of our '67 Mustang emptied out, we may upgrade the steering box and some other components. Look for related articles soon.

3. The old 302 comes apart. We'll reuse just about everything but the gaskets on the new 331 stroker.

4. It only takes about 30 minutes to tear down a motor. We'll knock out the freeze plugs before delivering to the machine shop.

The old main bearings were in surprisingly great shape -not bad for 200 passes shifting at 7000 rpm!

6. The old KB pistons show minimal wear, and signs of normal combustion (carbon build up is centralized around the exhaust valve.) These pistons and rods can be reused in someone's 302 with a little clean up.

7. We laid the new 331 crank, and a piston/rod assembly, in place temporarily in order to check for clearances as the crank rotates.

8. As suspected the rod cap screws just barely (0.005") clear the cylinder bore skirt.

9. Using some yellow paint the areas needed notching were identified. As you can see, every bore needs a little notch on the thrust side of the skirt at about the 12 o'clock position.

10. We rough cut the notch using a carbide cutting ball and an electric drill. We went back with a Dremel tool and stone bit to smooth it out. Only 1/8' deep notch is required, slighty more for the 347 crank.

11. While we had the carbide ball out, we chamferred the oil return holes in the lifter valley and also the oil filter mount. This simply helps the oil drain faster.

12. Before hauling the block off, we used a bore dial gauge to measure the taper in the bores, and also any out of round in the main bearing tunnel. We'll drop the block off and specifiy a 4.030" over bore, and no align hone on the mains since they checked out within specification.
While the block is being machined, we'll list out and purchase the gaskets and other materials we need. In Part II we'll put it all together. F/M


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