When it's time to rebuild your vintage Ford small-block, the long list of things required can have you examining the checkbook and those credit card balances. While it's true an engine rebuild involves a lot of time and money, you can still realize great performance and enhanced durability at a reasonable price if you plan and build wisely. Did you know you can build a 300-plus-horsepower V-8 for under $2,000?
Building this kind of power doesn't have to cost a fortune if you plan properly and choose the right combination of parts. There are also simple procedures you can perform during the building process that make light work of getting big power for the money. Horsepower and torque are like weight loss programs. We're so busy searching for the easy route that we forget the common sense approach. Diet and exercise is the surest path to weight loss. Choosing the right combination of parts and assembly procedures is the easiest path to making power. It's just simple common sense.
Today we're going to Trans Am Racing where Mark Jeffery will show us what's involved in a properly planned and executed Ford small-block build. We're going to show you how to get the most bang for your buck, and how we found stock replacement parts to be adequate for as much as 300-350 hp.
The engine we're working with sports a '68 C8OE 302 block. We're after a mild-mannered street engine that will still deliver 300-plus horsepower when the pedal hits the metal. To begin with, we will examine our selection of components for this budget build, and then look at some of the more important aspects of engine assembly where extra care will pay dividends in improved reliability and a longer service life.
This is a well-used '68 C8OE...
This is a well-used '68 C8OE block with the extended cylinder skirts designed to accommodate the 302's longer stroke. That is what makes it different than a '63-'68 289 block. Decking and align boring were not needed. A 0.030-inch overbore has been accomplished. New freeze plugs have been installed. Screw-in oil galley plugs have been installed for reliability. This is all low-buck machine work that accomplishes a lot.
Here's our factory 2MA nodular...
Here's our factory 2MA nodular iron crank just back from the machine shop. To clean up any discrepancies at the journals, both the main and rod journals have been machined 0.010-inch undersize. Speed Pro 0.010-inch oversize main and rod bearings get the nod. Any time you have machine work performed, the bottom end must be dynamic balanced. This isn't optional, it's mandatory.
We're using 4.030-inch Speed...
We're using 4.030-inch Speed Pro flat-top hypereutectic pistons (PN H120CP) with Teflon-coated skirts for reduced friction and increased compression. Reducing internal friction and increased compression are the keys to power. These pistons are fly-cut to clear up to 1.94-inch intake valves.
The factory C8AE Ford connecting...
The factory C8AE Ford connecting rods shown here (5.0885-5.0915-inches center-to-center) will easily handle the power. L & R Automotive Supply Company has reconditioned them and installed 5/16-inch ARP bolts, which works well for a 300-horse engine. One option is to have 3/8-inch bolts installed during rod reconditioning, which gets these rods to 289 Hi-Po/Boss 302 specs. This costs only marginally more.
Cam selection is an important...
Cam selection is an important issue. We've chosen a Crane flat-tappet hydraulic cam and lifter kit (PN 363902). This mild hydraulic kit is for '62-'84 221-302ci Ford small-block engines. This grind offers .456/.484 lift. The advertised duration is 260/270 degrees on 112-degree lobe centers. This is more aggressive than the 289 High Performance factory camshaft. For about $300 more, you can step up to a more aggressive roller camshaft and more power.
These are the factory C8OE...
These are the factory C8OE cylinder head castings for 302-2V engines with 58cc chambers professionally machined by L & R Automotive Supply Company--perfect for our flat-top pistons. These heads have a fresh three-angle valve job with Speed Pro valves and Crane springs, retainers, and keepers. Spring pressure is matched to the cam profile. These are actually Windsor foundry castings, not the Cleveland iron we usually see. Look to Power Heads for CNC-ported iron heads for under $700. Opt for 351W castings from Power Heads and make even more power.
Look What You Can Get For $2,000-$2,500
With common sense planning and execution, look at how much power your small-block can produce for under $2,500. These are three dyno pulls that demonstrate how much power you can make and why.
Pull 1 demonstrates what our 302 can do with the modest build-up we have just performed. This is with an aggressive flat-tappet camshaft and 302 heads. Expect 285-300 hp with 350 lb-ft of torque. With carburetor and ignition tuning, you can make the most of these numbers.
|PULL 1 |
|RPM ||HP ||TORQUE |
|2,000 ||127 ||333 |
|2,500 ||162 ||340 |
|3,000 ||198 ||347 |
|3,500 ||234 ||351 |
|4,000 ||264 ||347 |
|4,500 ||284 ||332 |
|5,000 ||285 ||300 |
|5,500 ||273 ||261 |
|6,000 ||244 ||214 |
|6,500 ||213 ||172 |
In Pull 2, we've opted for 351W heads with stock valve sizing. these cylinder head castings won't cost any more, and we expect a solid 300-plus horsepower, with 350-plus lb-ft of torque. for just a few bucks more, go with a 650-cfm Holley and a roller cam for eye-opening numbers.
|PULL 2 |
|RPM ||HP ||TORQUE |
|2,000 ||127 ||333 |
|2,500 ||163 ||341 |
|3,000 ||199 ||349 |
|3,500 ||236 ||354 |
|4,000 ||268 ||352 |
|4,500 ||292 ||341 |
|5,000 ||298 ||313 |
|5,500 ||290 ||277 |
|6,000 ||263 ||321 |
|6,500 ||234 ||189 |
Pull 3 takes the 351W head further with larger 1.94/1.60-inch valve sizing. Check it out--327 hp and 367 lb-ft of torque. Again, we suggest a more aggressive roller cam, larger Holley, and deep-breathing headers for substantial gains in power. Expect 350-plus horsepower and 375 lb-ft.
|PULL 3 |
|RPM ||HP ||TORQUE |
|2,000 ||126 ||332 |
|2,500 ||163 ||342 |
|3,000 ||202 ||353 |
|3,500 ||242 ||363 |
|4,000 ||279 ||367 |
|4,500 ||310 ||362 |
|5,000 ||325 ||341 |
|5,500 ||325 ||310 |
|6,000 ||305 ||267 |
|6,500 ||283 ||229 |
In the interest of good low-to-mid-range...
In the interest of good low-to-mid-range torque, we opted for this used Ford Motorsport aluminum intake manifold that we were able to find used at a swap meet. When combined with our higher compression ratio and a 600-cfm Holley carburetor, it will amount to a meaningful increase in power.
This is the Holley 4160 600-cfm...
This is the Holley 4160 600-cfm four-barrel carburetor. With its vacuum secondaries, electric choke, and easy tunability, it is more than adequate for this application. It's a great street carburetor. You can step up to a 650-cfm Holley for even more torque and horsepower.
This Speed Pro oil pump offers...
This Speed Pro oil pump offers us plenty of volume and pressure for a street application. A high-volume pump would provide more pressure than is needed in this application and would require a lot more energy to spin. Don't forget to blueprint your oil pump, checking side clearances and the like.
We're going with a Speed Pro...
We're going with a Speed Pro timing set, which features a double-roller chain and sprockets for less internal friction. The double-roller chain is far less prone to stretching than the factory style single-row timing set and costs only a little more. Consider this money well spent for precision timing and reliability.
As a final nod towards economy,...
As a final nod towards economy, we're opting for a rebuilt Autolite distributor with a new distributor cap and ignition wires. The Pertronix Ignitor electronic ignition retrofit will eliminate breaker points and improve drivability.
Our 2MA crankshaft has been...
Our 2MA crankshaft has been ground 0.010 undersize to true up the journals. Because Mark doesn't trust packaging labels, he checks the bearings and journals for proper sizing.
A micrometer is used to measure...
A micrometer is used to measure crankshaft journal diameter. Bearing clearances should be 0.0005-0.0015-inch on the mains, and 0.0008-0.0015-inch on the rods for small-blocks.
Main cap bolts are torqued...
Main cap bolts are torqued to a final value of 70 lb-ft. This should be performed in thirds. Crankshaft endplay comes in at 0.007-inch on this 302, which is right in the center of the acceptable range.
Each camlobe is generously...
Each camlobe is generously coated with camshaft assembly lube. This aids in the work-hardening of the lobes during initial fire-up and break-in.
After the cam is positioned,...
After the cam is positioned, the Crane dual-roller timing set is installed. Use a straight edge to line up the timing marks, and use Loc-Tite on the cam sprocket retaining bolt. We're using a Ford replacement two-piece eccentric designed for a mechanical fuel pump.
Bore sizing gets checked right...
Bore sizing gets checked right along with piston sizing to determine piston-to-cylinder-wall clearances. Because we are running hypereutectic pistons, there isn't the concern for expansion you would have with more expensive forged pistons.
Hypereutectic pistons use...
Hypereutectic pistons use a tighter average clearance of 0.018-inch, which contributes to their quiet operation. These are a nice compromise.
Before pistons are installed,...
Before pistons are installed, ring end gap must be checked. A good rule of thumb is 0.004-inch gap for each inch of bore diameter. An engine with a 4-inch bore calls for 0.016-inch ring end gap. Ring end gap determines internal friction. We want less of it while keeping good sealing.
Mark installs the pistons...
Mark installs the pistons using a billet ring compressor. For home shop use, an adjustable compressor works fine.
With the engine rolled over,...
With the engine rolled over, rod bolts are tightened down to between 19-24 lb-ft using a smaller 3/8-inch drive torque wrench. Do not tighten the rod bolts with the torque wrench until all eight piston/rod assemblies have been installed.
Connecting rod side clearances...
Connecting rod side clearances should size in at 0.012- to 0.018-inch.
Be sure to install the head...
Be sure to install the head gasket correctly, with coolant passages located at the rear of the block and with "FRONT" located at the front of the block. A backwards head gasket will cause overheating and engine damage. Torque the heads according to the factory crisscross sequence at a final value of 65-70 lb-ft.
Crane pushrod guide plates...
Crane pushrod guide plates are next. Use Teflon tape or liquid Teflon on the stud threads because you are screwing them into a water jacket.
Each valve lifter gets a coating...
Each valve lifter gets a coating of molybdenum grease at the lobe face before being inserted into its bore. Do this only with flat-tappet lifters. Lifter bores need engine oil or assembly lube to prevent seizure during start-up.
With the studs and guideplates...
With the studs and guideplates installed, it's time for rocker-arm installation and adjustment. Do this with the engine's firing order. Rotate the engine and watch valve timing events. When the intake valve closes and the piston is at top-dead-center, adjust the valves. Tighten the rocker arm adjustment to where the rocker is touching the valve stem. Then tighten one-half to three-quarter of a turn. Repeat for each cylinder.
Intake manifold and gasket...
Intake manifold and gasket installation requires caution. Fel-Pro Print-O-Seal gaskets self-seal well. However, use silicone gasket sealer around the coolant passages. With early small-block heads, cut the dog-leg part out of the gaskets for better coolant flow.
The dog-leg is a '69-and-up...
The dog-leg is a '69-and-up 351W thing and not applicable to the 289/302. Run a bead of silicone along the block rails. Stay away from the cork end gaskets provided--they leak.
Oil pump and pan installation...
Oil pump and pan installation wrap up this engine build. Check oil-pump-to-crankshaft clearances, then pick-up to pan clearances. You don't want the pick-up to touch the pan. Use sealer between the block and gaskets for best results. This reproduction oil pan is available from Mustangs Plus.
We like this Pro Street harmonic...
We like this Pro Street harmonic balancer. It is wider and a bit heavier than a stock Ford balancer. Our 302-inch small-block calls for the early style 28-ounce balancer. We've got an ARP balancer bolt and washer to secure the damper. Use the correct harmonic balancer installation tool. Torque the bolt to a spec of between 75-90 lb-ft.