5.0 Mustang & Super FordsProject Vehicles
Ford Mustang Engine Block - Project Real Street Part 1: Short Block - Getting Real
Kicking off our Real Street project with a Super Pro Bullet from D.S.S.
When we first began kicking around the idea of sponsoring the NMRA series, I wanted this magazine to sponsor a class for real people with real power-adder Mustangs. Street Renegade was approaching the 8s and Pure Street was about to run 10s, so there was a gap to fill. I suggested the name Real Street and NMRA's James Lawrence suggested rules similar to Factory Stock with a power adder. We went back and forth on various specifics of the rules, but in the back of my mind I pictured a prototypical car-a Vortech S-Trim, a Cobra intake, Trick Flow Twisted Wedge heads, and a D.S.S. short-block.
I had seen plenty of street cars running this type of combination, and I wanted owners of hot street Mustangs to be able to run this class. For the sake of competition we agreed on things such as a spec fuel and a stock camshaft, but those combination highlights I had in mind were all legal. Sure my prototypical car combination might never compete, but several similar setups surely will, and that was the idea-real cars with real parts.
Racing isn't cheap and it never will be, but the Real Street rules allow for the creation of a legal race car with a reasonable budget. Such financial considerations were one reason I had that D.S.S. short-block in mind. D.S.S. has long been mass producing durable, affordable small-block Fords. For about $2,999.95-depending on your cylinder head and piston combination-D.S.S. can set you up with a short-block capable of 650 hp and mid-nines, all housed in a stock Ford block.
Dubbed the Super Pro Bullet short-block, this combination offers us enough cushion for a Real Street combination to be durable in a stock block, which helps keep the cost down. If you needed to step up to an aftermarket block, a Ford Racing Performance Sportsman 302 or a full-boogie FRPP R302 block would increase your credit-card balance even more, but those blocks are really for running in Renegade and beyond. A Super Pro Bullet is plenty for a Real Street car, and Tom Naegele at D.S.S. says you could easily run one of their less-expensive Pro Bullet combinations in Real Street (see Affordable Option sidebar).
The pictures that follow are of our Super Pro Bullet 306 going together. Since Real Street mandates the use of a stock camshaft, we opted to run flat-top pistons with no valve reliefs for a bit more compression and power. However, if you think you might ever change classes and move to a more aggressive camshaft in the future, you might want to give up a hint of compression and save the hassle of pulling the motor apart to cut reliefs before you can install a hotter cam.
On the left is a D.S.S. race-prepped stock rod, which is found in the company's Bullet and Pro Bullet short-blocks. According to D.S.S. those rods are good for up to 575 hp, which should be more than enough for a Real Street engine. However, the rugged 4340-steel H-beam rod on the right jumps the engine's horsepower capabilities up to 650. The full-floating H-beam rods are better for high-rpm applications. They might seem to be overkill for Real Street, but we wanted a little extra durability, just in case.
Ordering up a Super Pro Bullet is like getting your burger all the way. Standard accessories in the engine include a Melling oil pump, a heavy-duty oil pump driveshaft, Fel-Pro graphite head gaskets, a Fel-Pro gasket set, and ARP head studs. D.S.S. sticks with a standard-volume oil pump, as it provides plenty of lubrication. Anything more is simply overkill and increased parasitic drag on the engine.
Even more important than the 4340 steel rods is the D.S.S. Main Support System, which allows a Super Pro Bullet to withstand the rigors of up to 650 hp with nitrous or supercharging. Basically the MSS secures the free end of the main stud with a 31/44-inch main web of harmonic dampening aluminum. This arrangement virtually eliminates main cap walk, which would lead to bad things such as cracking of main webs and breaking of crankshafts. Not only does the MSS go on without modifying the main caps, but it also allows the use of a D.S.S. optional Pro Tray windage tray. The tray keeps oil off the rotating assembly, which reportedly frees up 10-15 hp. It also keeps oil in the pan and air out of the oil, which D.S.S. says lengthens bearing life. The Pro Tray is a $139.95 option.
According to Tom Naegele at D.S.S., block prep is critical to engine durability and horsepower production. After the block is thermal cleaned, Magnafluxed, stress relieved, and has its threads chased with a tap, it is deck equalized. Tom says OEM block finishing is not ideal for head-gasket retention. He says stock blocks can be 0.010-0.015 different from side to side, and with 0.010 yielding a 11/44 point of compression, the difference will cost you horsepower from the two banks fighting each other. D.S.S. trues the decks to make each side equidistant from the crank centerline. What this means to you is you can torque your cylinder heads to 80 lb-ft all around, which produces better head gasket sealing.
Horse Sense: According to the '01 NMRA rule book, "5.0 Mustang & Super Fords magazine Real Street was designed for 'street-driven' 10- and 11-second, small-block, manual-transmission, power-adder Fox-chassis Fords, including '96-present 4.6-equipped Two-Valve Mustang GTs. Maximum 311 ci. 26.5 x 10.5-inch maximum tire size, as measured. 32-car qualified fields run on a pro tree (0.400) NHRA Sportsman ladder. Three qualified passes will be allowed on Saturday, with eliminations taking place on Sunday, weather permitting." For complete class rules, check out the NMRA Web site at www.nmraracing.com/classes2001/rs.html.
Ring seal is the number-one priority at D.S.S. because it's worth horsepower. So the company has developed a three-step honing process. According to Tom, the stones used, the amount of material removed per grit size, the pressure, and the speed are critical to the end result. D.S.S. hones each cylinder bore to 0.004 inch of its final measurement before the final honing is done.
From there, the machine operators bolt on a torque plate at 80 lb-ft. This plate distorts the bores just as the cylinder heads will, so when the final honing takes place the cylinders are extremely straight and round. All that means the rings will seal well, which retains combustion pressure in the cylinder and helps produce more horsepower. Tom says the ring sealing capabilities of these engines is typically worth 30-40 hp versus a non-torque-plate-honed engine. That number reportedly escalates to 60-70 hp on a supercharged engine such as our Real Street combination.
At the other end of the sealing equation is the head gasket. Super Pro Bullets come to you with an O-ringed block. In this process a ring is cut around each cylinder and a stainless steel wire tapped into the groove. This wire then helps retain the head gasket under severe pressures. D.S.S. prefers this method to others because it allows the use of a relatively inexpensive head gasket, and it doesn't require cylinder head machining. Another tip from D.S.S. is not to torque your intake manifold to more than 15 lb-ft. According to Tom, anything more could actually cause you to lose a head gasket.
Often it's the little things that kill you. One such seemingly minor point is the stock oil galley plugs. Tom says these often pop out, causing lost oil pressure. To remedy that malaise, D.S.S. taps and plugs the galleys.
Working with a stock crank and block means doing a bit of work to make them live at 650 hp. To that end, each stock crank is shot-peened, stress-relieved, Magnafluxed, precision-ground, and oil-scooped. Here, you can see the oil holes are ground so the leading edge looks like a scoop. This scoop shape feeds the rod bearings with oil sooner and longer for added life.
D.S.S. takes great care in measuring the rod and main clearances with a dial-bore gauge and a micrometer.
Once those measurements spec out, the engine is assembled using bearing assembly lube on the bearings and a light application of engine oil on the cylinders.
Once the short-block is assembled, a dial indicator is used to check the endplay of the thrust bearing. If everything measures up, the engine is ready to go to you, or be finished off as a long-block.
We opted for a completed long-block fitted with Trick Flow Twisted Wedge cylinder heads, so all we have to do is add an intake, headers, accessories, and an oil pan and we're ready to put the engine in the car-if the car was ready. Before torquing down the cylinder heads, D.S.S. used a set of lightweight checking springs and a dial indicator to check our piston-to-valve clearance. This measurement was particularly critical because we are running flat-top pistons with no valve reliefs. We had 0.125 on the intake and 0.225 on the exhaust with 1.6 rocker arms, and 0.100 clearance with 1.7 rockers.
By now you're probably thinking, Those magazine guys always build stuff stronger than it needs to be. I can run Real Street for less than that. Well, you're right. D.S.S. offers the prototypical combination for Real Street at about $1,000 less than our Super Pro Bullet. It's the Pro Bullet 306. The only differences between the two are the Pro Bullet uses prepped stock rods and it doesn't come with head studs or an O-ringed block. D.S.S. says the Pro Bullet will comfortably support around 550 hp and mid- to low-10s at 3,200 pounds, which should be all a Real Street racer will ever need.