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Modifying A 460 Ford Engine - A Bigger Better Big-BlockThis Large Displacement Beast Will Move You From the December, 2006 issue of Modified Mustangs & Fords By Wayne Cook Photography by Wayne Cook
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Every so often they get a customer at the Trans Am Racing engine shop who thinks a large displacement Windsor stroker just isn't big enough. For those folks, a 427 is at the bottom of the displacement range, not the top. These are the people who order a 385 series big-block engine for their project. The original 429s are getting fewer and farther between, and, for this crowd, the displacement baseline is 460 ci. The cubes just go up from there. For applications where over 500 hp is desired, a big displacement delivers the goods and eliminates the peaky characteristics of an engine that has to wind to the stars to make big power. The 385 series engine we have planned at Trans Am Racing is going to be sized at 545 ci. With this much displacement, stratospheric rpm levels won't be necessary to deliver the horsepower and torque numbers we're after. With a power level target of 600 horses, we're still going to need over 1-hp-per-cubic-inch. this is our goal, while simultaneously keeping the engine tractable enough to have acceptable street manners because the street is where this engine will be doing business. Home will be beneath the hood of a '69 Mustang Mach 1. The car has had the shock towers shaved to allow installation, and custom-made headers will also be required. We're going to start with a '74 Ford 460 block that has been cleaned up and bored 0.030-inch oversize. The relatively small overbore means that almost all of the extra displacement in our 545 is coming from a big stroke increase. The stroke length on the original 429 was 3.59 inches, while a 460 has a 3.85-inch stroke. The stroke length on our 545 is 4.50 inches. That's an increase of .65 inch, or almost two-thirds of an inch over the 460 and almost a whole inch longer than a 429. Let's see what parts TA Racing has selected for this build, and then we'll look in on the construction of the short-block. Next month we're going to top the engine off with the rest of our induction, including some customized Edelbrock cylinder heads. Then we'll take a trip to the dyno shop and see what the engine dyno tells us. Rings And Wrist Pins
Larger displacement strokers often use a special piston with the wrist pin location raised to accommodate a longer connecting rod. Sometimes, as in the case with our combination, the wrist pin will be moved up until it intrudes upon the oil ring lands. In a racing engine where the running time is limited, this situation isn't a problem. For a street engine, however, this is an undesirable condition. The opening underneath the oil ring can cause excessive oil consumption and fouled spark plugs. However, this condition can be controlled using gapless piston rings in conjunction with a lower support ring.  The reciprocating assembly...  The reciprocating assembly for this engine is available at Trans Am Racing (1531S-460, $1,850). this cast-steel crankshaft is manufactured by Scat and has a long 4.50-inch stroke. The cast-steel construction is a big step up from a gray-iron casting and is also less expensive than a forged-steel piece. Balancing the whole setup will run you $155 and is good insurance.  For piston rings, Total Seal...  For piston rings, Total Seal gapless rings (RM269035, $175) were selected. Although more expensive than conventional piston rings, they have a super-low 111/42-percent leak down. For an engine equipped with regular rings, expect a leak-down figure in the area of 8 percent. Every little bit helps, and any compression that stays above the rings means horsepower; any that leak down end up in the crankcase. This photo shows the rings required for one piston.  These connecting rods are...  These connecting rods are forged-steel construction and have an H-beam configuration. They were supplied by RPM Machine and have a 6.700-inch center-to-center length. The stock rod length for the 460 is 6.605.  The pistons for our build...  The pistons for our build are forged and 0.030-inch oversized. Manufactured by Probe, they have had the wrist pin relocated upward to accommodate the longer connecting rods. We selected the flat-top design to go with the large chamber cylinder heads that we'll be using for a final compression ratio of 10.5:1.  New bearings are important,...  New bearings are important, and these Clevite 77 bearings (CM74339-H, $90) should fill the bill nicely. Because our crankshaft is brand-new, we don't need to be concerned with any undersize considerations. Bearings for both crankshaft main journals and connecting rods are shown.  You can't go wrong using ARP...  You can't go wrong using ARP fasteners for a new engine. Here, we have enough to cover the whole build: main cap studs, head bolts, rocker studs, flywheel bolts, and a complete engine and accessory fastener kit.  Engine main cap studs instead...  Engine main cap studs instead of bolts are mandatory if a main cap girdle is to be used. This TA Racing girdle (1025R-460, $385) is cut from billet steel and will dramatically strengthen the bottom end of the two-bolt block. Main cap walk or wobble is virtually eliminated using the girdle. It's cheap insurance.  Comp Cams makes all of the...  Comp Cams makes all of the components for our valvetrain, including the Magnum rocker arms, hydraulic roller lifters, and camshaft. The camshaft in our engine (3637-000-1, $295) is a custom grind and has a lift at the valve of.627 inch for both intake and exhaust. Duration at 0.050 is 244 degrees for both intake and exhaust, and the lobe separation is 108 degrees. Although this sounds like a lot of camshaft with the .600-plus lift, the large displacement of our stroker big-block should be able to absorb all that lift capability quite nicely. Comp also furnished a double-row timing set for the project.  Here's our Ford 460 block...  Here's our Ford 460 block (the core cost us $250) just back from the machine shop. While there, it was checked over completely and found to be in good shape, needing only to be bored 0.030-inch oversize. Our total bill for machine work was right at $385. Unlike the short deck or Windsor small-block, this block doesn't need to be notched at the pan rails or the bore skirts to clear the lengthened reciprocating assembly. Mark begins assembly by installing the ARP main studs into the cylinder block using a hex driver to gently seat the stud.  All main bearing halves have...  All main bearing halves have been set in place in the block. Here, the upper half of the two-piece rear main seal is installed.  We're preparing for the installation...  We're preparing for the installation of the crank, so all bearing surfaces get a coating of assembly lube. The center main bearing is also the thrust bearing and is shown here getting the lube.  The critical moment has come...  The critical moment has come as the crankshaft is carefully lowered into position in the bearing saddles. The crank is very heavy, and care must be taken not to bump it against anything or knock any bearings out of position during installation.  Once the new bearings are...  Once the new bearings are installed, the main caps can go into position. Each cap is then seated with a few taps from a wooden mallet.  The stud girdle has been set...  The stud girdle has been set into place atop the main caps. Separate spacers between the girdle and the main caps are not needed since they are built into the girdle. These special washers are installed in conjunction with twelve-point nuts to secure the main caps and the girdle.  Each main stud is given a...  Each main stud is given a coating of moly lube to ensure accurate and consistent torque readings. The main studs are then torqued to a final value of 95 lb-ft.  Each critical specification...  Each critical specification in the assembly process has been checked beforehand for accuracy, but there are still some things to recheck one last time. We'll confirm the bore size to ensure the overbore is the desired 0.030 inch. The final reading is 4.390-inch bore diameter, which is correct. Stock bore diameter is 4.360 inches.  Before we begin piston-to-connecting-rod...  Before we begin piston-to-connecting-rod assembly, we check piston diameter to ensure we're in specs. Subtracting the piston diameter from the bore size should yield a piston-to-cylinder-wall clearance between 0.00281 and 0.00300 inch. Each of the piston-to-cylinder-wall measurements fell within the desired range.  Our pistons use a floating...  Our pistons use a floating wrist pin, so a press is not required for piston assembly onto the connecting rod. Be careful to orient the connecting rod and the piston correctly during the assembly.  Piston-to-rod assembly is...  Piston-to-rod assembly is completed using spiral locks at each end of the wrist pin.  Each piston receives a complement...  Each piston receives a complement of Total Seal gapless rings. Although gapless rings are far more expensive than conventional piston rings, they're not a lot of money when compared to the cost of the engine. Regular rings might cost $85 per set, while the gapless can cost $225.  Each connecting rod gets the...  Each connecting rod gets the mandatory coating of assembly lube before going together. Notice the rods don't have any bolts protruding down. The rod caps will be held in place by cap screws coming up through the bottom.  With rings and bearings installed,...  With rings and bearings installed, the piston is fitted with a ring compressor. This tool will prevent the rings from snagging on the edge of the cylinder bore during installation. Even though we don't have rod bolts to worry about, we still need to be careful not to damage the crank when installing the piston-and-rod assembly. Once the piston is started, it is driven down the bore with a mallet, and the rod end carefully seated onto the crank journal.  Down at the bottom end, the...  Down at the bottom end, the rod caps are attached. The RPM H-beam connecting rods come equipped with ARP 12-point cap screws.  We have a special handle to...  We have a special handle to help us install the camshaft into the block. Before installation, both the journals and lobes will get a coating of assembly lube.  The next step is to install...  The next step is to install the camshaft into the block. The trick here is to be gentle when going by the cam bearings so they don't become damaged or knocked out of place.  Once all the connecting rods...  Once all the connecting rods have been installed, they are torqued to 63 lb-ft, then checked for rod side clearance, which must fall in the 0.016-0.018-inch range.  Once the cam is in place inside...  Once the cam is in place inside the block, the cam retainer can be installed. Be sure the side with the small oil passage faces the block and use thread lock on the fasteners.  Here's our completed 545 cube...  Here's our completed 545 cube short-block ready for cylinder heads and all the rest. This short-block is available assembled from Trans Am Racing for around $3,600. Next month, we're going to trick this engine out with specially ported Edelbrock heads and a whole host of other top-notch induction components.  Here, the new Comp Cams timing...  Here, the new Comp Cams timing set (3121KT, $98) goes into place. Notice the cam sprocket has holes on one side but not the other. This creates a counterweight to balance against the fuel-pump eccentric. Once the eccentric is installed, the cog will be in perfect balance for a smoother running engine. Use thread lock on the single cam sprocket retaining bolt.  The wrist pin location on...  The wrist pin location on our 545 stroker piston has been moved up into the oil ring lands. This leaves the bottom of the ring groove open to the crankcase.  This photo shows the complete...  This photo shows the complete ring set for the oil ring groove on one piston. At the left is a lower support ring. This is a separate component from the regular ring set. From the bottom up, the order of oil ring installation is: support ring, lower oil ring, the expander, and, finally, the top oil control ring. With this four-piece ring set installed, the opening at the bottom of the oil ring groove is effectively closed. The sturdy support ring closes the gap, while protecting and bolstering the thin lower oil ring.  This is the second piston...  This is the second piston ring in the set. It is conventional in appearance and has the same end-gap requirements as an ordinary second ring.  Here's the gapless part of...  Here's the gapless part of the set. These two rings together comprise the top compression ring on the piston. The end gaps are installed opposite each other. The ring on the left has a small ridge built into it to accept the smaller ring and locate it in exactly the correct position.
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