Smart engine building
Street-savvy approaches to Ford performance engine building
Jim Smart - February 09, 2012 10:00 AM
Ford’s 1M and 2M cast iron crankshafts went out there in the 1960s and won races, which makes it a very durable piece even today. Your machine shop can make it better and stronger via common sense machining techniques, improved oil flow and wedge, radiusing/micro-polishing the journals, and shot-peening for strength. Icing on the cake is good dynamic balance. The best 2M cranks are the “2MA” castings for the 5.0L High Output engines. However, there are two considerations — a one-piece rear main seal and 50-ounce offset balance versus 28-ounce for earlier 289/302 engines because these are externally balanced engines.
Harmonic balancers act as a shock absorber for powerful combustion pulses. They control crankshaft twist. Begin your engine build with a new or reconditioned balancer from Mustangs Etc. All you need for the street is a stock balancer.
A good street engine will perform fine with reconditioned factory connecting rods and hypereutectic pistons. JGM Performance Engineering in Valencia, California, has built untold thousands of small-block Fords for its customers in 30 years using stock rods with 5/16- and 3/8-inch ARP bolts with great success. Shotpeening stock rods makes them stronger for a good 6,000 rpm engine. The 289 has 5.1545-inch C3AE rods center to center. The 302 has shorter 5.090-inch center to center C8OE rod forgings. The best 302 rods are 5.0L High Output forgings, which are slightly heavier rods, but very effective.
If you’re restoring a classic Mustang or vintage Ford, casting numbers and date codes are important. However, if you’re building a street engine you will be able to live with for years to come, go with a newer 5.0L block (they’re still out there) or at least a standard bore 5.0L roller block you can punch to 4.020- or 4.030-inches. The maximum you want to go with a small-block Ford is 4.040-inches. Do not let anyone convince you 4.060-inch bores are a good idea.
Before you spend a bunch of money on expensive machine work, have heads and block Magnafluxed for cracks and flaws.
Spend good money on durability — new valves, guides, and hardened exhaust valve seats. This sets your engine up for today’s harsh unleaded fuels and lays the pavement for 200,000 miles of reliable operation. Ask your machine shop to clean up chambers to remove potential hot spots, which can cause detonation. The largest valve you want here is 1.94-inches intake and 1.60-inches exhaust. Cheap power comes from the time-proven selection of early 351W heads. Watch out for chamber size on 351W heads. You want the smallest chamber possible — 1969-’71 vintage. Larger chambers lose precious compression.
Small-block Fords have been fitted with three basic types of rocker arms — conventional, rail style, and stamped steel (bolt fulcrum). In our experiences, the conventional and stamped steel rocker arms have always been the best choices. Stamped steel, positive stop rocker arms have been in continuous use on small-block Fords since 1977 and have been used on 5.0L High Output engines with great success. Rail style rocker arms, which entered production in May of 1966 and were in production until 1977, are to be avoided at all costs because they will not stand up to high rpm operation. As they wear, they touch valve spring retainers, posing great risk to engine life. One more thing, always install adjustable screw-in rocker arm studs and guide plates.
JGM Performance Engineering recommends the use of Viton valve seals in street and race applications because they’re durable — outlasting Teflon and umbrella seals by a wide margin. This is good money spent on durability.
If you’re determined to keep a stock, stealthy demeanor and want to stay with iron heads, PowerHeads offers professional CNC porting on stock Ford heads and does it better than anyone out there. Go with an early 351W head and some of that good CNC porting from PowerHeads.
The age-old debate about piston selection and which type you should choose depends on mission. If you’re on a tight budget, go with cast pistons for predictable expansion properties and price. However, if you have the budget, opt for hypereutectic pistons, which are high-silicon cast pistons. Hypereutectic pistons deliver strength, less weight, and predictable expansion properties for nearly the same money as cast. Forged pistons are unnecessary for most street engines and money wasted if you’re just going cruising or plan occasional weekend drag racing. Forged pistons have aggressive expansion properties and are noisy in a cold engine because they need greater tolerances.
A good machinist understands how to fine tune machine work to where you reduce internal friction, get liberal oil flow, yet maintain a good oil wedge at the same time. It should all fall between minimum and maximum factory tolerances for best results.
Money well spent regardless of budget is on dynamic balancing. It is money you must spend. Go the extra mile and aim for the best dynamic balancing you can find. Vibration not only wastes power, it shortens engine life.
Most of us tend to install oil pumps right out of the box. Money ahead is to have your oil pump blueprinted by MCE Engines in Los Angeles. They will take your oil pump and examine clearances, check the relief valve, and deburr the casting. You can install your blueprinted MCE pump and enjoy peace of mind. Oil pumps must also be checked for counterweight to pump clearances because there’s the risk of contact even in a stock application. Do a mock up and check rotation before final button-up. The crank must clear the pump by at least .060-inch or more.
The Pertronix Ignitor system is the easiest drop-in modification you can make, and it takes about 30 minutes. The Ignitor, Ignitor II, and Ignitor III eliminate ignition points in old Autolite/Motorcraft distributors, not to mention some of the more popular aftermarket ignitions. Smooth idle. Crisp performance. No sweat.
A great investment in your engine build is a professional dyno break-in and tune. The average is $600 to $1,000 a day, which is money well spent for an engine that’s ready to install and use when you get it home. Dyno tuning consists of ignition timing, valve adjustment, fuel system tweaking, and a leak check. A reputable dyno shop will have a variety of carburetors for you to try out, a complete set of jets, and right-sized headers to get your small-block dialed in.
Flat tappet technology is old hat and has no purpose in today’s engine builds even if you’re building a stocker. Less internal friction means more power.
Reduce friction in your stocker while giving it the crisp sound of mechanical lifters. Solid roller tappets give your small-block Ford the soft Hi-Po chatter while reducing internal friction and delivering more power.
Another friction reducer is a dual roller timing set with thrust bearings. We reduce friction two ways: by improving load distribution with a dual roller and giving the cam and crank gears a smoother ride.
Holley offers a variety of four-barrel carburetors for small-block Fords. For 289/302 stockers, all you need is a 500 to 600cfm Holley #1850, which has been the standard replacement four-barrel carburetor for small-block Fords since the 1960s. Don’t forget the old reliable standby, Autolite’s 4100, available from Mustangs Etc. and Pony Carburetors in 480 and 600cfm sizes.
Ever looked at factory horsepower and torque numbers and wondered how they arrived at these numbers?
We’ve all heard this time and time again — 500 horsepower for under five grand on pump gas. Yeah, right. It’s one of the greatest tales ever told by car magazines, however, it’s not always realistic or affordable.
Oh sure, you can build a 500-horse small-block that will run on pump gas for under $5,000 — maybe. But, will it stay together for 100,000 miles? Any way you slice or dice horsepower and torque, they cost money. Durability costs even more. The more power you envision, the more money you better be able to envision in your bank account.
And, the more power you build into an engine, the less longevity you’re going to get, because excessive amounts of power are hard on an engine. So what about compromise you can live with? How much power do you really need for the street and how much are you willing to give up in cash and assets to get it? Time for truth — who really needs 500 to 700 horsepower on the street?
Instead, what about an affordable street small-block that will last you years and hundreds of thousands of miles — a great cruising engine you can live with that will get you onto the freeway quickly? And, when it’s time to show off and smoke the tires, you’ll have the torque to do it. Ford’s magnificent 90-degree Fairlane V-8, introduced in 1962, known to most of us as the small-block Ford, is one of the easiest engines to build and make power with. Although most of us know the small-block Ford for that legendary SCCA B-Production winning magic number — “289” — there have been more 302s produced since 1968 compared to the 289’s short five-year production life a half-century ago.
Regardless of which displacement you desire — 289 or 302 — basics for these engines remain the same. You have two choices using the 289/302 block. You can go with the stock displacement with a “1M” crank (2.87-inch stroke for the 289) or the more common “2M” crank (3.00-inch stroke for the 302) and build on that foundation to make a healthy 250 to 320 horsepower. Or, you can go with any number of affordable cast steel crank/H-beam rod stroker kits out there for about the same amount of money and get upwards of 400 to 450 horsepower.
Taking your 289/302 and stroking it to 331 or 347ci and making a bunch more power costs roughly the same amount of money when you factor in machining costs to all that old factory iron. With a budget cast steel crank, heavy-duty rods, and hypereutectic pistons along with 347ci and early 351W cylinder heads, your 289/302 can make in excess of 400 horsepower.
Affordable stroker power is available from Scat Enterprises and is easier to get than you think. Remember, the time-proven rule still applies — there’s no replacement for displacement — and it’s so easy to get it via the budget stroker kit. Budget stroker kits with cast steel cranks, H-beam rods, and forged pistons run approximately $1,200 to $2,000, which is a great bargain when you consider the power gained.
One more hint: do you know the quickest path to horsepower and torque? Compression. Increase compression and watch power grow substantially. However, remember today’s octane ratings and keep compression below 10.5:1. Then, watch coolant temperature closely and keep an ear out for spark knock.
If you’re going to build using a stock crank and rods, you can still get a lot of torque with the right camshaft and cylinder head combination. No pie in the sky — just 250 to 320 honest horsepower with a comparable amount of torque from the basics Ford has handed you. Where small-block Fords fall short is cylinder head port design, which can be improved with help from PowerHeads and CNC porting, if you desire a stock iron head. The aftermarket offers limitless possibilities when it comes to high-performance aluminum cylinder heads.
On The Dyno
Ever looked at factory horsepower and torque numbers and wondered how they arrived at these numbers? We have too and decided to chat with JGM Performance Engineering in Valencia, California, and came up with some small-block Ford numbers.
Ford’s factory numbers for the 289-4V high-compression V-8 is 225 horsepower and 305 lbs-ft of torque. When JGM Performance Engineering decided to rebuild and dyno test one of these engines built for a ’65 Mustang, it came up with 212 horsepower and 285 lbs-ft of torque. Though these numbers are short of the factory mark, they tell us something about what can be done to free up power. This was a fresh engine with tight tolerances. Given several passes over several days, numbers would have improved with wear in.
Had the JGM 289-4V engine been fitted with a roller cam and rocker arms, numbers would have been significantly higher due to reduced internal friction and a more aggressive cam profile. How much more? Easily 30 to 40 horsepower and comparable torque in the 330 lbs-ft range. JGM’s stock 289-4V engine was fitted with an 480cfm Autolite 4100 carburetor. Given 600cfm, even more gains in horsepower and torque. When you start looking at small improvements, they add up to big gains. Advancing or retarding ignition timing will make a difference in power coupled with significant jet swaps.
Though Shelby American advertised its 289 High Performance Cobra V-8 at 305 horsepower, JGM decided to build and test one of these engines as well turning in 291 horsepower and roughly 300 lbs-ft of torque — again short of factory numbers. However, there are reasons why. JGM’s Cobra Hi-Po was fitted with a 600cfm Autolite 4100 carburetor (for a GT350H with automatic), which held horsepower and torque down. Fit the Shelby Hi-Po with a 700 to 750cfm Holley carburetor and watch this engine come alive, meeting its full potential.
It isn’t so much the big improvements you make to a small-block Ford that get you power, but a whole bunch of small changes that add up to big power. And when you have the opportunity to put your small-block Ford on the dyno with a proven engine tuner, watch what happens with each and every tuning step that adds up to real world power.
For Your Information:
Holley Performance Products
JGM Performance Engineering
Summit Racing Equipment