Classic Mustang HP1556: Restoration, Repair & Upgrades

INTRODUCTION

It started as little more than a restyled Falcon. With its long-nose, short-tail styling and standard equipment like bucket seats and floor shifter, the new 1965 Mustang appealed to the emerging Baby Boom generation that was just entering the work force. Ford hoped to sell 200,000; they sold over one million in the first year, launching a phenomenon that continues to this day. From 1965 to 1973, the first generation Mustang was a sports car for everyone. Today, untold thousands continue to be coveted by their owners.

Since 1978, Mustang Monthly magazine has been guiding ’65—’73 Mustang owners in their ongoing quests to improve their cars. Through how-to and technical articles, the editors have tackled everything from basic maintenance chores to the most elaborate restoration procedures. With the recent trend toward modern upgrades, we’ve covered many of the ways to add performance, comfort, and convenience with late-model electronic fuel injection, power windows, and rack-and-pinion steering. Our goal is simple—help readers improve their vintage Mustangs for however they plan to use them, whether it’s a weekend driver, show car, or even everyday transportation.

Classic Mustang: Restoration, Repair & Upgrades is a compilation of popular and helpful tech stories from the editors of Mustang Monthly magazine. Inside, you’ll find informative articles covering engine rebuilds, suspension tips, basic maintenance repairs, sheetmetal replacement, and performance upgrades. Three decades ago, Mustang Monthly pioneered the easy-to-follow how-to format, and that’s what you’ll find here. Each technical article will guide you along step-by-step as you repair or upgrade your Mustang, whether it’s a basic six-cylinder hardtop or a fire-breathing Shelby.

Inside you’ll find a guide for aligning your Mustang’s front end, replacing an old exhaust system with a brand-new concours version, installing rack-and-pinion steering, optimizing your cooling system, restoring exhaust manifolds, and more.

Improving your vintage Mustang is the goal, and that’s what this book is all about.—Donald Farr

Editor, Mustang Monthly

ENGINE & DRIVETRAIN

Chapter 1

How to Build a Budget 289

Text and Photos by Jim Smart

Mark Jeffrey of TransAm Racing took on the challenge of freshening up our Mexican block 289 within a strict budget.

This Mexican block 289 has been hanging around our garage for at least six years, collecting dust and rust. When a Southern California machine shop built this engine six years ago, they started with a 4.040-inch-bore block we thought we could save. The machine shop, no longer in business, was able to hone the bores at 4.040-inches and fit them with forged pistons. The crank was turned 0.010/0.010-inch undersize. The C3OE 289 connecting rods were reconditioned and fitted with new ARP bolts.

When we began planning a project to show how to convert a six-cylinder Mustang to a V-8, we weren’t sure where we would source our small-block engine until we remembered this old dust bunny. Perhaps a gut feeling was the reason we bagged this engine and never touched it again. The irregular appearance of the cylinder walls bothered us, so there it sat inside a plastic bag for six years.

When we blew the dust off and took the engine to Mark Jeffrey at TransAm Racing, he looked it over and knocked it down for a freshening up. Mark didn’t like the way the bores looked either. He hauled the block, crank, rods, and pistons out to L&R Automotive Supply Company in Santa Fe Springs, California, for inspection, machine work, and a recheck of the dynamic balancing. Then, he brought it all back to his shop for assembly.

Now we’re going to confess one of our more memorable screw-ups with the hope you don’t make the same mistake. When we found this Mexican block 289 eight years ago, it was in a ’66 Mustang that had been sitting for years. We tore the engine down to see what was inside and learned that machine shops and engine builders can make mistakes by assuring you the castings and forgings you’ve brought them will probably work fine. We accept their word because we don’t want to search for another engine block or spend the money to get it.

In the world of engine building and car restoring, there are no free lunches. If something is on the ragged edge of acceptable, it’s a throwaway unless you want trouble later on. This logic applies to driveline components, body panels, seat upholstery, electrical system, suspension and braking systems, engines, and personal computers. If something is marginal, it’s best to cut your losses and start over with better stuff. This is the main lesson of this budget Mexican block 289 build.

When a Simi Valley machine shop accepted this engine for a freshening up years ago, it didn’t exhibit proper judgment when deciding to clean up and hone a 0.040-inch-overbore block. As engines power our Mustangs, the cylinder walls experience the extreme cycling of heat, cold, and friction. Pistons travel millions of times back and forth in the bores for thousands of miles at extremely high temperatures. This cycling process alters the molecular structure of the iron, which considerably changes a perfectly dimensioned cylinder bore. When we refer to a seasoned block, this is exactly what we mean. A seasoned block or cylinder head has been cycled thousands of times through heat and cold, helping the iron castings settle into relative normalcy. On the down side, cylinder bores tend to taper and warp with operation. When cylinder-bore taper exceeds 0.011-inch from top to bottom, it’s time to cut a fresh bore to the next oversize, typically 0.020, 0.030, 0.040, and 0.060 inch. This creates a perfect cylinder devoid of irregularities.

This is our justmachined’68 Mexican 302 block, easily identified by the casting number (C8AM) and the hump in each side of the front of the block. L&R Automotive Supply has rehoned the bores to 4.040-inches with room for piston growth. The line bore has been checked. Decks didn’t need to be cut. It’s ready for assembly.

Our bottom-end rotating assembly consists of a 1m crank with a 2.87-inch stroke, reconditioned C3OE rods, and Speed Pro-forged flat-top pistons from Summit Racing Equipment. Cast or hypereutectic pistons would have been enough for cruising. Forged pistons are overkill for a weekend driver. Ductile iron rings are ideal for this application.

Mark sets the 0.010-inch oversize Speed Pro bearings from Summit Racing Equipment. He sets them dry, with no lubricant between the bearing and block. He uses assembly lube on the bearing surfaces before setting the crank. Here’s one example of where overkill can cost you. These are race bearings, also known as H-bearings, installed by a Simi Valley machine shop years ago. Hard-surfaced race bearings are designed for steel cranks and hard use, not cast cranks in street use. Whenever you set the bearings, check oil-galley passages for proper alignment.

Two-piece rear main seals do not have to leak. Mark uses good old-fashioned Permatex Form-A-Gasket between the seals and rear main grooves. He staggers the seal end gaps away from the main bearingcap parting lines to minimize the risk of leakage. He also lays down Form-A-Gasket between the main cap and the block.

Older generation small-block Fords were equipped with rope rear main seals from the factory that used this pin to keep the rope in place. Rebuilders tend to forget the pin during the rebuild process, leaving it in place and damaging the new rubber seal. Our Simi Valley machine shop made this mistake and left the rope-retaining pin installed, which damaged the rear main seal. Mark caught this error and removed the pin.

From the factory, 289/302/351ci Fords had a 4.000-inch bore—exactly four inches. The 221ci and 260ci Fords (’62-’64) had smaller bores. To make the bores perfect again after thousands of miles of use, they can be bored to 4.020, 4.030, 4.040, or 4.060 inches in diameter. A good rule of thumb with small-block Fords is to bore 0.020- or 0.030-inch oversize on a standard 4.000-inch bore, then 4.040-inches on a 4.030-inch bore, but no more than 0.040-inch oversize. If racing, it’s best to limit yourself to a 0.030-inch oversize in the interest of safety and security. Some like to punch the bores out to 4.060-inches, 0.060-inch oversize, but this is strongly discouraged. If you’re determined to bore your block to 4.060-inches, have it sonic-checked first to ascertain cylinder-wall thickness.

Our Mexican block 289 had already been bored to 4.040-inches, but bore taper wasn’t too bad, well under the mandated 0.011-inch taper. Our original machine shop concluded the cylinders could be honed and fitted with new 4.040-inch forged pistons, but the visible irregularities in the cylinder walls when the engine was assembled disturbed us. We could see low and high spots in the walls amid the fresh crosshatch pattern. The machine shop assured us the engine would perform well.

When Mark Jeffrey saw our cylinder bores, he had the same concerns about the irregularity’s impact on reliability. Because we were building a budget 289 for the Six to Eight project, we both concluded it was probably a passable block, and we were just worrying too much. When the block came back from L&R Automotive Supply, it had a fresh 4.040-inch hone and appeared ready for assembly. As Mark prepared the block, gut feelings continued to hound him, as well as us. He was disturbed by the cylinder wall irregularities he could see with the naked eye. We decided to go for broke and assemble the short-block anyway. When Mark assembled our short-block, he learned a couple of disappointing facts. One connecting rod was hung on the piston backwards, a formula for disaster. Connecting rod chamfers always go toward the crank journal radius. The machine shop made the error, and mistakes like this happen to even the most talented professionals. This is why you must always double and triple check everything before closing up.

Mark fills the pinhole with high-temp RTV silicone sealer. You can also use JB Weld. Make sure the surface is smooth before installing the seal.

Before permanently installing the crankshaft, measure the main-bearing clearances. Mark installs the main-bearing caps and torques each of them to 60-70 lb-ft. This sets the main cap up with the bearing at installed sizing. He checks the main-bearing diameters with a dial-bore gauge. Then he checks the crank journals with a micrometer. Clearances should be 0.0008 to 0.0015 inch. Our 1m crank fits these main bearings perfectly.

REAR MAIN SEAL TRICK

It’s so easy to make a mistake at the rear main seal and wind up with an oil leak. Again, you want the two-piece seal end gaps positioned away from the main-cap parting lines. Apply Permatex Form-A-Gasket between the main cap and block. Coat the seal tips with Form-A-Gasket. Carefully fit the #5 main cap in place and observe the seal installation. Make sure the seal tips groove into the cap smoothly.

Notice liberal doses of engine assembly lube on the crank-journal seal-mating surface. Also note the seal lip is correctly positioned toward the inside. Apply Form-A-Gasket to the main cap mating surfaces and seal the ends for added protection against leakage.

As Mark hand-cranked and checked the engine with each piston/rod installation, he couldn’t help but notice resistance in one narrow segment of rotation. He removed the pistons one at a time and checked each bore with a dial bore gauge. Some of the cylinders were not true despite L&R’s best efforts to get them straight, and regardless of the 0.011-inch taper rule, piston binding is piston binding. Our block was unacceptable for use.

We did have one option: to bore the block to 4.060-inches and order new 4.060-inch pistons. Because we wanted a fiercely reliable 289-inch small-block, we elected to pass on our Mexican block and order a replacement. Derek Ranney of L&R Automotive Supply set us up with a fresh vintage 302 block that was machined, bored, and honed to 4.040-inches.

Originally, we considered a hydraulic roller camshaft for our Mexican block 289. Because a roller cam and all of the related components can run upwards of $500, we decided to build a conventional small-block with a flat-tappet camshaft. This is an Isky Super Cam flat-tappet hydraulic camshaft with 0.278/0.278-inch cam lift, 0.445/0.445 valve lift, and 208/208 duration on 108 lobe centers. This means a smooth idle with good off-idle throttle response.

Mark coats the cam journals with assembly lube. The lobes get molybdenum grease for proper break-in.

We could have taken a chance with the C8AM 302 Mexican block with its distorted cylinder walls, and may have had a fine engine that could have gone 100,000 miles, or we could have wound up with an engine that had to come out of the car at 5,000 miles because the rings didn’t seat properly. It’s cheaper to replace the block before it goes in the car than doing it all again later. This is where a decision has to be made on the side of caution. Our greatest failing was not recognizing the distorted cylinder walls during the machining process before assembly began.

Our formula here is designed for a mild, reliable, street small-block for those who want to get into V-8 power without breaking the bank. You can save money by taking a common-sense approach. Rule one is don’t plan more for your engine than it needs. Weekend cruisers and commuter cars do not need forged pistons, big valves, roller cams, big carburetors, headers, or single-plane manifolds.

Mark gives the crankshaft ends a whack with a mallet to help center the crank on the bearings.

The main caps are torqued from center outward to 60-70 lb-ft of in three increments. First torque is 20 lb-ft, then check rotation. Next, 40 lb-ft for freedom of rotation. Finally, 60-70 lb-ft and check rotation. Our main saddles are happy and the crank turns freely. Double check all main cap bolts.

Check piston rings for proper gap locations. Ring end gaps should be positioned at 9, 12, 3, and 6 o’clock.

Next, Mark checks crankshaft endplay with a dial indicator. Endplay is how much the crank moves back and forth in the main saddles and should be 0.004-0.008 inch.

The cylinder walls are lubed with engine assembly lube, but you can also use SAE 30-weight engine oil.

Mild street engines need what it takes to be reliable, which is mostly just good engine-building technique and extra pains to ensure the engine is built properly. Most of those pains won’t cost you a dime. If you want to improve on your budget small-block and have extra cash, here’s where you should spend your money:

• Roller hydraulic cam with under 0.500-inch lift for reduced friction and better performance

• Base-level roller rocker arms, like the Magnum from Comp Cams, to reduce friction and improve performance

• One-piece pushrods for reliability

• Autolite 4100 four-barrel carburetor from Pony Carburetors

• New generation dual-plane manifold, like the Edelbrock Performer RPM or Weiand Stealth

• Autolite or Motorcraft distributor with PerTronix Ignitor II electronic conversion

• Heavy-duty ignition wires

• Cast-aluminum valve covers with thick steel-reinforced gaskets

• Closed crankcase ventilation system for cleaner air

• High-flow water pump

• Ceramic-coated shorty or long-tube headers.

Hit the Swap Meets and eBay

We saved money on our budget rebuild by thinking used on the things that didn’t affect engine integrity. Intake manifolds, carburetors, valve covers, distributors, and other items can be found for a song in the classifieds, at swap meets, and on eBay. For our Budget 289 effort, we unearthed an old Ford Motorsport dual-plane manifold and a Holley 600cfm carburetor for next to nothing from someone who decided to go with something else years ago and never installed the stuff. Ditto for the Scott Drake Cobra valve covers that you can’t get new anymore. There’s always something out there someone didn’t want. Take advantage and save.

Another great way to save money is buying old speed equipment from the ’60s. There’s nothing like a set of old Cal Custom finned valve covers or an Edelbrock F4B high-rise manifold to get your motor running. We’re beginning to see these pieces on period restomods and retro-rides in our travels. We thought most of this stuff was gone, but pieces surface periodically at the shows to help us remember a golden era.

Sources

Comp Cams

www.compcams.com

Ed Iskenderian Racing Cams

www.iskycams.com

Holley Performance Products

www.holley.com

L&R Automotive Supply Co.

www.lnrengine.com

Summit Racing Equipment

www.summitracing.com

TransAm Racing

www.transamracing.net

We found this old Ford Motorsport dual-plane manifold for a bargain on eBay. Items that you may think had long ago disappeared may very well be available online.

Budget Building Tips

Mark uses a custom billet piston-ring compressor to install each piston and rod assembly. He has already checked the ring end gaps.

There are a lot of misconceptions when it comes to bearing installation. One basic rule is to install main and rod bearings dry—no lubrication between the bearing and block. A dry surface enables the bearing to remain anchored to the block. Keep in mind there’s a tiny amount of crush going on between the bearing and block which keeps the bearing secure. Always use engine assembly lube or engine oil between the bearings and crank.

When building a small-block Ford or any other Ford with press-in oil-galley plugs, replace the press-ins with screw-in oil-galley plugs to keep the oiling system safe. There are three passages in front.

Because rod bolts are harder than cylinder walls and crankshaft journals, it’s easy to nick a cylinder or chip a crank with the rod bolts during installation. Rod bolt protectors are available at machine shops and performance parts stores. If on a tight budget, use fuel line or transmission cooler line hose—as we did—for protection.

Fel-Pro gaskets are the gasket of choice for any engines we build. This is the performance set with Print-O-Seal gaskets for added security from Summit Racing Equipment.

L&R Automotive Supply provided us with these C5OE cylinder-head castings. These ’65 289 heads have 53-57cc chambers and very little quench area, which minimizes detonation, perfect for the Speed Pro flat-top pistons we’re using. We’re going with stock valve sizing at 1.78/1.45-inches. For a bit more power, opt for larger 1.94/1.60-inch Chevrolet valves. L&R also machined these heads for screw-in rocker-arm studs and pushrod guide plates. Stock valve springs with dampers were installed to go with our mild Isky cam.

Clearance is important where the piston meets the cylinder head. Our 289 has approximately 0.020-inch of deck height, which is the distance from the top of the piston to the top of the block deck. We will check this with a dial indicator. When we install the Fel-Pro head gasket, this clearance will increase by at least 0.010-inch or more. This affects compression.

Ford buffs like Mexican blocks for the high nickel content. But the real gold in a Mexican 289/302 block isn’t the block at all, but the wider main bearing caps like those used on ’63-’67 289 high-performance blocks. A 289 Hi-Po block isn’t all that unique. It’s the same casting as a 289-2V/4V block. The wider main bearing caps make it special, and the same can be said for a Mexican block. If you have a bad Mexican block, don’t throw it all away. Save the main bearing caps for another block.

Chapter 2

A Basic Small-Block Rebuild

Text and Photos by Jim Smart

This 289 is proof that you don’t have to decide between your kids’ college education or a rebuild for your Mustang.

Over the years, we’ve shown our readers how to build lots of engines. In many cases, we’ve opted for forged pistons, roller cams, aftermarket induction systems, striking dress-up goodies, and more. But this stuff costs a lot of money. So how do you get into a fresh, reliable engine without having to mortgage the farm? We’re going to show you with help from Jim Grubbs Motorsports and Federal-Mogul. We’ll also show you options that will make your basic engine build even more productive, depending on your budget.

In addition, there’s the option of purchasing a low-buck crate engine from a national discount auto-parts chain. But the problem is, you don’t always know what you’re getting. Mass-production rebuilders tend to have a one size fits all mentality. Your ‘65 Mustang may have come with a 289 V-8. However, the chances of getting a 289 from any of the national chains are slim. You’re going to get a 302, with a smattering of components from four decades of small-block Ford production. The block might be an ’81 302 casting, while the heads might be mismatched, one from 1978 and another from 1983. The problem is, combustion chamber sizes can be different, making compression ratios different on each cylinder bank. You probably won’t notice it, but it does affect engine longevity and performance.

Tips for a Successful Engine Rebuild

When we rebuild an engine, we go inside and make it like new. But what does that mean? An engine rebuild consists of the teardown, inspection of the permanent parts we’re going to machine and reuse, and assembly of the engine using new parts as necessary. Here’s a good blueprint to follow for a successful engine build:

• Disassemble and inspect all components, and thoroughly clean the ones you’re going to reuse. All block and head plugs should be removed and the oil passages should be wirebrushed and checked for blockages. Water jackets and passages should be inspected and cleaned. Chunks of rust should be removed.

• Check the block and heads for cracking and inspect the crankshaft for irregularities and cracks. Inspect the connecting rods for irregularities. Bore and hone the cylinders to the next oversize (but never over .040 inch).

• Check the line bore, and hone or bore as necessary, although boring is rarely necessary.

• Check the block deck surfaces and mill only as necessary. Measure crankshaft journals and machine to the next undersize only if necessary. Otherwise, polish the journals for good oil control and bearing mating.

• Recondition the connecting rods and install new bolts.

• Install new cam bearings.

• Install screw-in oil gallery plugs anytime there are press-in types.

• If equipped with a manual transmission, resurface the flywheel.

• Thoroughly wash the block with soap and water. Wire-brush the oil gallery passages to ensure removal of metal shavings, rust, and other debris. Do the same with the crankshaft oil passages.

• For the heads, go with a three-angle valve job with new valves and guides. If you’re going to drive your Mustang daily, install hardened exhaust-valve seats. If you’re building a show car or an occasional driver, you can pass on the hardened valve seats.

• Invest in a good, high-volume oil pump. Have your machine shop disassemble the pump and do an inspection, and make sure they check the pump rotor side clearances and machine as necessary. Have them check the pressure relief valve for proper operation because not all oil pumps leave the factory in correct operating condition. Invest in a new oil pickup as well.

• Be sure to dynamic-balance the rotating assembly for smooth operation and longevity.

• Check ring end gaps, even if you’re using pregapped rings. Assume nothing.

• Opt for the best gaskets money can buy, such as Fel-Pro Print-O-Seal. And use the best silicone gasket sealer while you’re at it.

• Go with a roller hydraulic camshaft if you can afford it. Install a dual-roller timing set for less internal friction.

• Opt for a high-flow water pump for best cooling efficiency.

• Paint oil-flow areas with a high-heat paint to improve oil-return flow.

• Use brass freeze plugs because steel plugs will ultimately rust out.

• Install a new timing cover from California Pony Cars. They are the best reproductions out there.

• Go with a new harmonic balancer from Mustangs Etc. They are identical to original equipment.

Getting Started

When disassembling an engine, be mindful of its problems and ready to move in the right direction when they’re discovered. Our 289 was removed from a ’65 Mustang convertible. The original owner passed on and left the car to his nephew, Jeff Fischbach. Jeff was just getting off the freeway when the engine developed a knock. He knew his uncle had the engine rebuilt a few years earlier, but he didn’t know the specifics.

Disassembling an engine requires detective work. Our job was to determine what happened to make the engine inoperative. We knew by the sharp metallic knock that Jeff’s 289 was ill. We began our investigation while the engine was still in the car, starting it to try