At a recent track outing,...
At a recent track outing, we clicked off a 10.33 at 132.8 mph. In an effort to dial up the boost, we wound up splitting the stock 5.0 block and mortally injured our engine about 30 seconds after this picture was taken.
I am the coupon-clippin' clown who spends the bare minimum to make my car faster. Sure, a paint job or a few more hard-core race parts would be nice, but as the Champion of Cheapness, I spend only what I can afford. When someone talks price, all I hear are the birds screaming, "Cheap, cheap, cheap!" Some call it an act of stubborn ignorance; I call it arthritis of the wallet. Many laugh at my Mickey Mouse contraptions, but they work and for quite some time. But even I have to admit, they work only up to a certain point.
For the past two years, we've been flogging our street-driven '91 GT with 15 pounds of turbocharged boost and have lit the Chrondecks with 10.30 e.t's. Our 66mm turbo still cranks out nice, clean boost, and the HP turbo kit looks great after two years of mixed usage. Our big-dollar Lentech AOD is still banging away, and the TFS top-half works just as good as the day we bolted it onto our stroked 347 short-block. For quite some time, many couldn't believe that our production block was lasting this long, but we credit it to two things-good machine work and a soft tune that Mustang Magic gave us to help keep things alive.
We're happy to report the...
We're happy to report the soft street tune in our EEC IV has proven to be quite reliable up to this point. Just a week before the engine blew, it produced 480 hp at the wheels at 5,400 rpm on Mustang Magic's DynoJet chassis dyno.
Mustang buffs intimate with the 5.0 are painfully aware of the delicate production block and its inherent lack of strength. The 98-pound casting sometimes works in 11- or 10-second cars, but once you start throwing power adders at it, the stock iron lump is simply useless in containing all the rotating bits. It's terribly thin internally, especially in the main web areas where it will deform under any type of enhanced cylinder pressure that comes with high horsepower. So it will not surprise you to hear that the stock block in our Mustang finally gave up the ghost. This is how it went down.
It was a beautiful day at Raceway Park in Englishtown, New Jersey. The MM&FF staff members were busy photographing some pretty cool readers' rides and were chewing the fat about all sorts of stuff-new power adders, the NOPI girl bikini contests, and of course, the huge plume of smoke that was coming from our GT at about halftrack. From behind the wheel, yours truly felt the car begin to slow down during another test run. I shut it down, jumped out of the groove, and luckily, still had enough momentum to reach the return road. There's nothing worse than looking in your rearview mirror and seeing a contrail of white smoke while asking yourself, "I wonder what fluid that is?"
Upon disassembly of our injured...
Upon disassembly of our injured soldier, we found all sorts of carnage. The split block fractured a few main caps and even broke the oil-pump assembly-the latter wound up starving a few of the main and cam bearings in the process. The TFS main girdle helped us get two years out of this stock block, so we can attest that main girdles do help, but they do not permanently solve the weaknesses of the stock E7 casting.
We've broken many stock blocks...
We've broken many stock blocks before, and each time they split at the same place, alongside each main saddle. The main webs completely failed in this engine, relinquishing this once finely machined engine block into a 98-pound lump of scrap.
The cracks run deep, with...
The cracks run deep, with fissures going all the way up to the lifter valley. Upon further investigation, we concluded that the cause was from main cap walk, forcing the two main cap bolts apart and subsequently, complete failure.
With the broken pieces removed...
With the broken pieces removed (which fell out on their own), the incredibly thin main webs were exposed. How these didn't fail any sooner is a testament to the good machine work we received and the soft engine tuning that was skewed for durability, at the expense of extra power.
We rebuilt our 347 with World's...
We rebuilt our 347 with World's Man O' War block. Weighing in at a hefty 190 pounds, it checks in at nearly double the weight of a production block. Needless to say, the accompanying added strength is worth the weight in gold. For you weight-conscious fanatics, an aluminum version is also available. We ordered ours in the stock 302 8.2-inch deck height with stock 2.248 main sizing so that we could reuse all of our internal and external items such as the intake manifold, valvetrain, and rotating assembly.
World uses billet-steel main...
World uses billet-steel main caps for maximum tensile strength and four-bolt design for positive retention. The caps are also doweled to the block for precise alignment. The center three caps have splayed end bolts to offer greater clamping strength as the cap is retained beyond the normal linear plane. ARP hardware is used throughout.