June 1, 2005

What's The Bore?In the Nov. '04 issue, the In Search of Mustangs column indicates that a 289 engine bored .040 should be considered a "throwaway" when rebuilding. What is the maximum bore you recommend?Birl AdamsWhitefish, MT

Engine-block castings do not have to be absolutely identical to each other, because precise areas will be machined to perfection after the casting is complete. A good casting is one that allows for the original machining without regard for future machining operations. Ford small-block engines have enough material in the cylinder-bore area to allow for a finished cylinder diameter of up to 4.030 inches and still provide enough material for proper cylinder-wall strength. This is common to any typical block casting from the Ford foundry. Some castings may have come out better than others and will have a more uniform, thicker cylinder-wall area that allows for an additional overbore, up to .060 inch in some cases. Simply stated, all small-blocks can be safely bored .030, while some can tolerate up to .060.

To determine a cylinder wall's thickness, the engine builder or machine shop can perform a sonic test. Should the block prove to be exceptional with thick, round walls, an .040 or .060 bore is OK. Sonic testing is expensive and not all machine shops have the equipment to perform the test. It's much simpler to use any block and limit the overbore to .030.

Power AlignmentI have installed power steering in my '69 Mach 1. The water-pump hose is on the left side, but my power-steering bracket might be for a right-side water pump. The bracket is a little off. Is there a difference between righthand and lefthand brackets?Gary MakarVia the Internet

The brackets do indeed differ slightly and can lead to alignment problems. As you mention, the problem is relatively small. With a bit of filing and a few spacers, the power-steering pump can be properly aligned.

Head SwapI have a '67 Mustang fastback with the 289 two-barrel engine. I recently upgraded to a four-barrel Edelbrock intake and carburetor, and recently got my hands on a set of stock heads from an '89 5.0 engine. Would it be worthwhile to install these heads? I also obtained a set of 1.7 rocker arms.Larry WaughColorado Springs, CO

Because the late-model 5.0 heads are basically a copy of the 289 heads currently on your engine, there is no advantage if you install them. The roller rockers, however, increase the camshaft parameters, but not as much as they would with a 5.0 camshaft. I suggest you switch to the Edelbrock camshaft that's designed to complement the carb/manifold combination. The Edelbrock folks have spent countless hours on the dyno to develop these packages, and they make good power without sacrificing driveability. A good performance exhaust system is also in order, utilizing headers as your budget permits.

Six-Cylinder DiscsAs a new subscriber, I don't know if you've answered this before. I've owned a six-cylinder '66 convertible for nine years. I rebuilt and installed a 351 Windsor, FMX transmission, and a 9-inch rearend out of a '69 Cougar. My only problem is the factory four-lug six-cylinder brakes on the front. All of the disc-brake kits do not bolt to the six-cylinder spindles. What's my best option to get better braking and possibly a dual master cylinder for safety?Dan BaberBuchanan, MI

You'll have to install V-8-style spindles in order to install disc brakes on an early six-cylinder car. Replacement of the small spindles is a good idea regardless of brake choice because the six-cylinder spindles are prone to breakage. They also utilize undersized wheel bearings that are prone to failure.