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289 to 302 Engine Build

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by Jefferson Bryant  More from Author

Adding More Cubes Is Easy on You and Your Wallet

Packing a few extra cubes into that 289 may not seem like a big increase and it’s not, but it’s also really easy. We recently had the opportunity to punch up the cubes on a ’66 289 that needed a rebuild for our ’65 Mustang coupe project, and we went for it. A friend had a 302 rotating assembly with brand new .040”-over pistons, .010-under crank and stock rods for super cheap. The 289 block had been rebuilt about 50,000 miles ago, but had a rod that was knocking on heaven’s door. It needed some attention before getting dropped between the fenders of the ’65. As it happens, the 289 had been bored .040 when it was rebuilt and the cylinders were in great shape.

The only real difference between a 289 and a 302 is the stroke of the crank. A 289 has a stroke of 2.87”, while the 302 runs out at 3”, the cylinder bore is technically different, with the 302 running an additional .002”. The extra stroke provides about the same horsepower, but the real difference is in the bottom end. According to our dyno software (Comp Cams’ Desktop Dyno), the 289 with the same cam and cylinder head profile would put out 299 hp and 350 lb-ft (4,000 RPM) peak output, but the 302 version will put out 297 hp with a peak torque of 363 lb-ft with a lower RPM peak (3,500 RPM), which is enough to feel stoplight to stoplight.

Rebuilding a basic street motor is a simple task, but attention to detail and cleanliness is everything in an engine build. We spent a few days cleaning and prepping the block and all the parts to make sure everything was in order before the assembly took place. We did not have the block machined, we checked the cylinders and other than a very slight ring land, they were in excellent shape. Besides that, .040”-over is acceptable but boring a 289 block .060” is really starting to push the boundaries for a street block without adding hardblock to the water jackets. We are not saying it can’t be done, but we had all the parts we needed and this is a budget build up. While this motor is getting changed to a 302, the process is all the same for any small-block Ford.

To prep the block, we used a couple of old-school tools for the cylinders-a ridge reamer and drill-powered cylinder hone. As a piston rides in the cylinder, the walls wear down over time. This creates a ledge called ring land. This needs to be removed for a proper build. The ridge reamer cuts away the ring land and if done properly, won’t affect the rest of the cylinder walls. If you have more than a couple of thousandths of ring land, then you need to have the cylinders bored. The other tool we used is a cylinder hone powered by a cordless drill. This breaks the glaze on the cylinder walls and proved the crosshatch pattern you want to break in the rings.

We purchased all of our replacement parts from Summit Racing, including the cam, gaskets, water pump, oil pump and even a new crank damper. We selected a street performance cam with a .471” lift, 276 duration (218 at .050). This is a good balance for fuel economy and performance for our daily driven ’65 Mustang Coupe.

We rebuilt the engine over the course of a week, and managed to keep the build under budget. The 302 rotating assembly cost $150, the rest of the parts were purchased from for a total of $432. This brings the total build price to $582, not bad for a fresh 300-hp 302.

We removed the oil pan and started pulling bolts. Before you remove anything, you need to mark each rod cap and rod for position. Use a stamp set and mark only one side with 1-8 respectively. If you flip a rod cap, it won’t line up just right and will ruin your new engine.

This is why the engine needed to be rebuilt. As you can see, the main bearings were wiped out, the rod bearings were about the same and the cam bearings were even worse.

Here’s a little tip – use a long bolt as a handle to remove the camshaft. We were going to replace the cam bearings anyway, but if you are hoping to reuse them, you need to be careful not to nick them while removing the camshaft.

The ridge reamer in action. By dialing in the blade and working slowly, you can remove only what is needed and not damage the cylinder walls. If you don’t remove the ring land, then you risk damaging the pistons or breaking a ring. Note that the lifter valley has been treated to a coating of Glyptal (from, which speeds up oil return to the pan.

We used a stone cylinder hone to break the glaze from 50,000 miles of use and to add the crosshatch to facilitate ring break-in. You don’t need much, just a light pattern. A few passes are sufficient.

The crank had been sitting for a while with some goopy prelube on it. This held some moisture under it and we found some surface rust when we cleaned it off. We dressed the journals with a little 1500-grit wet/dry sand paper to remove it, then thoroughly cleaned it, including all the oil passages.

We ordered all of the consumable parts from Summit Racing. All of these require cleaning before installation. The original damper on the 289 was separating, so we had to go for a new one.

After the block had been cleaned, our cam bearing installer (from Comp Cams, #5312) was used to install the new cam bearings. The machine shop gets $150 to install bearings, but with this tool you can install them yourself. It pays for itself in two jobs.

Next, the new .010” under main bearings were placed in the block. Don’t forget to prelube the crank side of the bearings. We use Royal Purple’s synthetic Max-Tuff assembly lube, it works great.

We reused the stock main cap bolts and torqued them to spec (70 lb-ft) in three increments. Don’t forget to replace the rear main seal on the rear main cap. We used a digital torque wrench from Gearwrench to get accurate readings on all of the bolts on the 302.

We cleaned pistons and rods with some degreaser to remove the old pre-lube off and to get the pistons perfectly clean before they get installed in the block.

The pistons came with ductile iron rings, which we installed using the spin-on method. You can use a ring spreader, but we have had bad experiences with breaking rings that way. If the ring has a dot on it, it always goes up.

A soft hammer handle is the best device for tapping the pistons into the bore. Make sure you protect the rod bolts from scratching the crank journals. We used some fuel line, which also helps guide the rod onto the crank. If you are unsure of the original position of the rods, the large chamfer on the crank-end of the rod goes against the crank, the little chamfer goes to the inside. If this gets swapped, there won’t be enough clearance between the rods. Before being slipped into the block, each piston was soaked in a bucket of transmission fluid which lubes the cylinder walls better than oil for the first firing.

When installing the caps, it is critically important to ensure the caps are lined up as they were removed. Don’t forget the assembly lube!

Next the cam was installed. We wiped each lobe with the supplied lube and used the Royal Purple Max-Tuff on the bearing journals. You don’t want to use synthetic lube or standard pre-lube on the cam lobes, especially for flat-tappet cams. The bearings must be installed dry, otherwise they could end up spinning in the block, closing up the oiling passages, and that would be bad.

The timing chain was installed next. We will be using an electric fuel pump, so we didn’t need the fuel pump eccentric, but we installed it anyway, just in case we ended up wanting to use a mechanical pump later.

The lifters were treated to a little dab of cam lube before being installed in the block.

We used a new set of Fel-Pro head bolts (had them lying around, price – $21 per side). Before threading them into the block, they were coated with some ARP thread lube, but 30w motor oil works too.

Don’t forget the oil pump drive rod between the block and the oil pump, forgetting that would render the engine junk as soon as you cranked it. The new Summit oil pump was installed with the original pickup tube.

The front timing cover is also part of the oil pan seal, so the mating surfaces have to be flush with each other.

The new pan gasket drops on in two sections, a dab of silicone where the cork matches up to the rubber seals keeps the pan from leaking at the joint.

We heated the Summit crank damper in an oven as per the instructions and drove it on with a hammer. Next, the motor was rotated to TDC on the compression stroke so we could set the valve preload.

With the lifters on the bottom of the cam, the pushrods were rotated as the rockers were tightened. As soon as the pushrod stops moving up and down (zero lash), the rocker is tightened ¼- to ½-turn. We went with 1/3-turn to achieve the .020”-.060” preload. Once the cam is broken in, we will recheck the preload. Too little preload is better for a flat tappet cam on initial firing than too much, which can flatten the lobes. The motor was rotated for each cylinder to ensure the lifters were on the bottom of the cam.

The intake gaskets were placed on the motor. Again, we used some silicone to seal the cork end gaskets to the head gaskets.

Next, the water pump was installed to the motor. All these bolts need a little antiseize to keep the threads from rusting.

We dropped the distributor in the motor, but it’s going to have to come back out right before the engine is fired up so we can prime the oiling system.

This is the final assembly of the 302. We have a set of Hooker headers for the engine. Those will go on right before it goes in the car.

Since we are using a flat tappet camshaft, the break-in oil is critical. You cannot use standard motor oil for a flat tappet camshaft, the EPA has forced removal of all Zinc and Phosphorous from standard oils. Zinc helps keep the fresh metal from breaking down with metal-to-metal contact. We use Comp Cams’ Break-In Oil, which has all the necessary additives for initial break in. After initial break-in, we switch to Royal Purple.

Parts list

302 Crank, pistons/rods (with new bearings and rings) $150
Sealed Power cam bearings FEM-1204M $21
Summit damper SUM-163289 $77
Fel-Pro gasket set FEL-KS2328 $62
Summit oil pump SUM-122168 $31
Summit timing chain SUM-G6620 $38
Summit Cam and Lifters SUM-K3601 $111
Sealed Power pushrods $27
Summit water pump SUM-312432 $65
Total $582


COMP Cams®
(800) 999-0853

Eastwood Company
(800) 343-9353

Danaher Tool Group
(800) 688-8949

Royal Purple, Inc.
(888) 382-6300

Summit Racing
(800) 230-3030


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