Jim Smart
March 1, 2007
Photos By: Benton Jackson

Special Thanks to Marvin McAfee, from MCE Engine, for his technical expertise and knowhow.

When Blair Jennings of Santa Barbara, California, called Marvin McAfee at MCE Engines in Los Angeles, his voice and story were familiar. Blair's father, Allan, who passed away many years ago, once collaborated with Marvin on his engines. They enjoyed a terrific friendship and working relationship centered on fast cars and the scream of high-performance Ford engines. When George Folmer, Parnelli Jones, and Dan Gurney were cutting apexes in SCCA Trans Am competition approaching 40 years ago, Marvin was building competition engines for people like Blair's father-and Blair was there to witness it all through the eyes of a child. After losing track of Marvin for the better part of a lifetime, Blair rediscovered him through a recent story in Mustang & Fords.

At his Santa Barbara shop, Blair had a 427W stroker all in pieces for his '66 Mustang Street Trans Am car that was under construction. He didn't know where to turn for engine-building expertise until he read about MCE Engines in our magazine. That's when he called Marvin for a long-overdue hello. Stunned by a call from someone he hadn't seen in 36 years, Marvin was eager to shake Blair's hand. He was also saddened by the loss of Blair's father and a friendship that quietly slipped away over time. Inspired by that friendship, Marvin did something he and the MCE team don't normally do. He chose to build Blair's engine using parts MCE Engines didn't specify to begin with. MCE Engines has a house rule: All parts must be MCE approved. Blair was the rare exception. Because he and his father were treasured friends, Marvin broke his own rules and worked with what the younger Jennings brought him.

Blair wanted what was almost impossible to achieve-an all-out racing engine with good street manners. We're talking Webers, a radical cam-shaft, big Edelbrock Victor heads, and a dry-sump oiling system. Marvin and the MCE team felt like Blair might be off his rocker. They took his dreamy-eyed idea and looked at what could be done with it.

Formula For Big-Inch Success

Blair did the right thing when he ordered his 427W stroker kit, opting for a Probe Industries 4340 super-strong steel crank, H-beam rods, and forged SRS flat-top pistons. Edelbrock Victor heads were an excellent choice for Blair's 427W, yielding 2.08/1.60-inch valves, large ports, and 62cc chambers designed for better quench, i.e., rapid flame travel across the top of the piston.

Blair dreamed of having Weber carburetion-something his Bow-Tie buddies did not have. But Weber carburetors are not easy to own and maintain. They look terrific, and under ideal circumstances they perform extremely well. Webers are as close to fuel injection as you can get with a carburetor. Marvin's concern was the minimal clearance Blair's Webers would have beneath his Mustang's cowl-induction hood. It wasn't just a performance issue, but a safety one as well. Because fuel vapors, called "stand off," tend to form immediately above each carburetor at high rpm, the risk of ignition in a confined area is what concerned Marvin most. He knew from years of experience that Blair needed a lot of room above his Webers. This remained a challenge for Blair as of press time.

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Formula For Big-Inch Success (Cont'd)

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Race Attitude - Street Demeanor

When Blair brought his 427W to MCE Engines, he learned quickly he made the same mistake as a lot of us: He didn't properly plan his engine project, and he ordered parts that don't always work well together.

Blair wanted the awesome look of Weber carburetors, but he didn't consider the sacrifices that must be made to have them. He opted for a radical high-rpm roller camshaft without considering what he would be giving up on the street. Blair chose the Edelbrock Victor cylinder head, which is an excellent head for high-displacement 351 Windsor strokers. Even at low rpm, the Victor works well when you're huffing lots of displacement. Victors were a good choice.

Marvin scolded Blair for his part selection, pointing out that too many of us package big-inch small-blocks like they're still small-blocks. Martin stressed that when you stroke a 351ci small-block to 427 ci, you no longer have a small-block, displacement-wise. You have a big-block, with much greater displacement and power than you had at 351 ci. That means you must feed the hungry small-block like a big-block with larger fuel lines, bigger ports and runners, a larger carburetor or throttle body, and so on. You also need to have a driveline that will stand up to the horsepower and torque a big-block makes. When you increase displacement, you must raise the bar in every way.

Balancing Act

Although dynamic balancing is optional (extra cost) with all engine builders, it is a necessity to engine smoothness and longevity. It is manda-tory at MCE Engines, but Marvin takes it a step further with his own disciplined approach to dynamic balancing. He weighs everything before it goes to Automotive Balancing, then AB precision balances everything to Marvin's own specs.

Dynamic balancing happens for the same reason we balance tires-to remove shake and vibration. Centrifugal force is an ugly thing when spinning and reciprocating parts are not in perfect balance. All pistons, rings, and bearings must weigh the same. Engine oil must also figure into this equation. Pistons and rings must weigh exactly the same as crankshaft counterweights. They should dance around each other smoothly, with the precision of a Swiss watch.

With dynamic balancing, each piston is machined down to the same weight as the lightest piston. Rings and pistons are weighed together as individual assemblies. All rods must weigh the same as the lightest one. To get it all in balance, remove metal from the heavier parts to get them down to the same weight as the lightest part. The same can be said for the crankshaft.

Internally balanced engines can be balanced independently of the harmonic balancer and flywheel/flexplate. Externally balanced engines, like the small-block {{{Ford}}} and FE-Series 428 Cobra Jet big-block, call for including the harmonic balancer and flywheel/flexplate in the balancing process.

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Camshaft Tech Talk

When Blair brought Marvin his 427W in a basket, he also brought an aggressive hydraulic-roller race cam from Schneider Racing Cams. This is an off-the-shelf bumpstick ready for racing. Blair wants to use his '66 Mustang fastback on the street as well as the track, though. Here are his cam specs:

Schneider Racing Cams Grind No. 284-RH
Running Specifications
Running Duration:284/284 degrees
Lobe Centers:112 degrees
Lobe Lift:.340/.340 inch
Valve Lift:.544/.544 inch
Peak Torque:3,500-5,000 rpm
Specifications At .050-inch tappet height
Intake Open:2 degrees BTDC
Intake Closed:42 degrees ABDC
Intake Centerline:110 degrees ATDC
Exhaust Open:46 degrees BBDC
Exhaust Closed:-2 degrees BTDC
Exhaust Centerline:114 degrees BTDC
Duration at.050 inch:224/224 degrees
Cam installed 2 1/2 degrees retarded (to enhance horsepower)

Duration and lift will prove the most challenging for Blair. When you're shopping for a cam, duration, lift, and lobe centers are the main concern. A lobe center of 112 degrees isn't the issue here-duration and lift are. Because duration is 284/284, which is rather lengthy, this will affect both idle quality and manifold vacuum. The same can be said for valve lift, which also robs vacuum and idle quality. Duration has a direct bearing on valve overlap (the period when both valves are off their seats). Overlap helps power on the high end, but hurts idle and manifold vacuum down low. These elements are what will make Blair's Mustang restomod a chore to drive on the street, yet incredible when it's time to go road racing. Our message here is simple: You cannot have both superior street and race qualities in the same engine.

What Is a Dry-Sump Oiling System?

This is what a typical dry-sump oiling system looks like. Shown here is a three-stage pump (actually three pumps-one for pressure and two for scavenging). You can have as many stages as you want, depending on how much scavenging you need. Generally, there is one stage for pressure and at least one stage for scavenging. In this application, we have one pressure stage (capped) and two scavenging stages. The scavenge ratio is 4:1, which means it has the capacity to return way more oil than it receives. This means more power because an efficient scavenging system will reduce crankcase pressure.

A dry-sump oiling system does away with your engine's conventional oil pan and internal pump, replacing them with a beltdriven external pump system and low-profile oil pan. Dry-sump oiling systems are designed specifically for racing even though they may be used in street applications. They are used in racing to ensure a constant supply of oil under high lateral g-forces and hard acceleration, which is crucial to engine survival at high rpm.

Because racing engines demand a continuous supply of oil under pressure at high rpm, a dry-sump system is designed to keep them well supplied. Conventional wet-sump oiling systems can develop oil supply problems at high revs, cavitating the oil pump and causing an oiling system to areate (suck air), causing major engine damage in nanoseconds. At high rpm, an engine's internal oil pump can empty a deep-sump racing oil pan, rendering moving parts dry in short order. At high rpm, all of the pan's oil winds up at the top of the engine, filling valve covers and the lifter valley completely-robbing important moving parts of pressurized lubrication. The dry-sump oiling system gives us more control of where the oil is. A dry sump gets oil back to the reservoir (oil tank) as quickly as it leaves.

A dry-sump oiling system consists of an external multistage, a beltdriven pump, cog-belt drive pulleys, high-pressure hoses and fittings, and a special dry-sump oil pan. The pan is designed to channel oil back to the pump and reservoir. When we speak of pump stages, we're talking individual pumps (stages) designed to move oil. Typically, there is one pump to provide oil under pressure to give us an oil wedge between moving parts. Then, we have at least one scavenge pump stage to collect oil and return it quickly to a reservoir. We can scavenge oil where a deep sump pan would normally be. We may also scavenge oil at the lifter valley and even high up at the valve covers. Much depends on the kind of driving we're going to be doing.

Reunited and It Feels So Good

Here is Blair Jennings at an SCCA Trans Am race at Riverside, California in 1970. That's the Grabber Blue Boss 302 campaigned by Jefferson Enterprises, powered by an MCE-built Boss 302.

Blair met Marvin long ago when he was in adolescence. At the time, Marvin was building race-winning Boss 302 engines for SCCA Trans-Am competi-tion. The Grabber Blue '70 Boss 302 Mustang campaigned by Jefferson Enterprises went after big game with a Boss 302 engine built by Marvin's Competition Engines (MCE). Blair's father looked to Marvin for his expertise-and he got it, using powerful small-blocks from MCE Engines.

As the fever of intense Trans-Am competition faded and faces changed, Marvin moved on, and so did Blair and his father. It would be more than 30 years before Marvin and Blair saw one another again. More than a year ago, Blair brought his engine to Marvin for a second generation of Jennings engines built by Marvin's Competition Engines.