We decided to feature this...
We decided to feature this engine build in a two-part series in order toget a little more in depth. We're shooting for 600 hp, and that soundsachievable. But read on for the stipulations we belted ourselves downwith. Do you think we can do it? Tune in next month for the part twofinale.
What makes for a great street engine? For the normal public, fueleconomy, reliability, low maintenance, and decent power probably sum itup. For us, when considering our dual-purpose Mopar toys, the attributesare probably not too radically different, except in how we define theterms. Good fuel economy? Might be that getting into the teens ratherthan 6-8 mpg is accomplishment enough to feel good about economy.Reliability? This might mean not having to worry about the engine for atleast a decade while clocking 3,000-5,000 miles a year. Low maintenancemay just equate to checking the fluids, getting in and driving, withouthaving to re-adjust the valves every few months. What's decent power?For the average motorist, it might be defined as enough get-up-and-gofor nimble acceleration in traffic and on-ramps. Decent power for aMopar enthusiast may well mean having enough on-hand to tear trenches inthe asphalt and to take out anything that dares challenge on the openroad.
In contemplating a powerplant for my own street driver 'Cuda,these same questions looking for answers came to mind. What would be agreat street engine? This machine wasn't being built as an everydaycommuter, mind you, but it would be nice to be capable of extended roadtrips, anytime, anywhere, at the twist of the key. It would be nice topull power brakes and A/C without the engine wanting to stall at idle,maybe with an easy 12 inches or more vacuum at idle. It would also benice if that idle would sit between 800 and 850 rpm without the clatterand instability of a deep lope.
The foundation for our 'Cuda...
The foundation for our 'Cuda engine build-up was this seasoned 440block, a retired .030-inch over bored dyno test block. The 1970 "F"block had seen duty in many configurations, and had survived over 750 hpon nitrous. The block had been decked approximately .070-inch when usedwith low-compression SpeedPro 2266 flat-top pistons, and also had thedecks grooved and fitted with copper O-rings.
Sure, a melodic and steady rhythm ofpower from the headers, exhaust, and cam is acceptable, but not thatragged-edge big-cam stagger that blows out enough toxic hydrocarbongasses to make your eyes water. It would be nice to have the quiet,maintenance-free operation of a hydraulic flat-tappet camshaft. It wouldalso be nice to a have a torque curve that starts right when you can useit, pulling strongly against a high gear ratio at low rpm withoutstumbling. Better still if that torque will carry up the rpm ladder tomake peak horsepower in the neighborhood of 6,000 rpm. So far, the goalsaren't too difficult to achieve, but wouldn't it be nice if it made asavage 600 hp on the street? That would be a great street engine.
Theengine we are building here is an attempt to meet these insanelyincompatible objectives with a regular 440 without any overly exoticcomponents, but rather through a carefully considered parts selection.
Machined years ago by Precision...
Machined years ago by Precision Speed and Machine in Bakersfield,California, the bores still measured with negligible wear after hundredsof dyno pulls. We simply touched up the cylinder walls with a brush honeto break the glaze and thoroughly cleaned the block. We were ready tobuild.
For the majority of its previous...
For the majority of its previous life, the engine had run a set offactory LY rods, which, in the engine's last configuration, were honedfor floating piston pins, but not bushed. A steel-on-steel combinationon the rod small end and pin can survive for a while on the dyno ordragstrip, but wouldn't be our choice in a street application. Thisbuild was the perfect opportunity to upgrade to Scat's H-beam rods,which come bushed and are far stronger than the stock rods. The internalengine components were weight matched in preparation for dynamicbalancing.
Although this engine was destined...
Although this engine was destined for the street, we were intent onpushing the reasonable upper limits of pump-gas compression ratio. Wewent with SpeedPro number LF2295 forged domed-pistons, which are a tadon the heavy side by today's race piston standards. But with our plannedupper rpm limit of about 6,500, they are a reliable and proven choice.With products from Tech Line, we coated the pistons with moly on theskirts and a thermal barrier on the crown.
A virgin factory-forged 440...
A virgin factory-forged 440 crank was ground .010/.010-inch on the mainand rod journals, and then balanced for our combination of internalengine components. The bobweight worked out to 2,681 grams.
ARP main studs were the only...
ARP main studs were the only upgrade to the bottom end. We had run thesemain studs in the engine's prior life, and as can be seen, the mainshave never been line honed or bored.
Fully grooved Clevite bearings...
Fully grooved Clevite bearings were fitted to the saddles and bastedwith Royal Purple assembly lube to prep for receiving the crank. Bigblock Mopars with aftermarket oil pumps provide plenty of oil volume forthe fully grooved bearings.