To start this Rat off with...
To start this Rat off with the right foundation, a factory four-bolt GM big-block core was located and refurbished like new.
Lately, so many people have been adding a 1/4-inch stroke to small-blocks and building 383-cid engines that it's become kinda boring. Aren't there any other stroker combinations you'd be interested in? And let's face it: although 480-plus hp 383s are cool to be sure, they've become rather ordinary. Wouldn't you rather have a snarling 700hp stroker Rat under your hood? Especially if those horses still drank pump gas and roared with enough bravado to scare anything but the most serious power plants back into the shadows? We're going to build a killer stroker big-block for cryin' out loud!
Not that building a 496-cid Rat is really all that unusual either. In fact, we've done it twice in the very recent past. Once with the 8.1L (that equals 496-cid) Coolest Rat (November 2002, March 2003) that dyno'd with 615 hp running Holley's MPI electronic fuel injection and squeezed 950 hp on NOS. And most recently (July 2003), we built a slightly smaller 490-cid Real Road Rat that cranked out 540hp and 550 ft-lb of gut-wrenching torque! And both of these engines were designed for a single purpose, to be driven daily on the street. But, there's still a giant gap in there.
A set of 1/2-inch Milodon...
A set of 1/2-inch Milodon main studs were installed and the block was align honed to perfect specs.
While we think that most of our readers love to learn about engines that they can build for their everyday traffic battle, there's also a large segment out there that are not satisfied with run-of-the-mill performance. They're not happy to be making just as much horsepower as the next guy. And they usually want everyone to know when they've begun rolling down the block. They want the crowds to part as they pull into the cruise night with their rumbling Rodent shaking windows and eardrums for blocks around. We're talking about lots of show with enough go to back up any boasts. We're talking about 700-plus hp on pump gas from a motor that rumbles lumpier than a Top Fueler with blown a head gasket!
How'd we get from there to here, you might be wondering? Well, we thought it was about time we showed you not only how to build a real powerful street motor, but we'd also show you how to build it so you'd get noticed. Typically, that means a loud idle and big exhaust. But, even a little 305 can make lots of noise, but can't back it up with that much power, so when you open your hood, you've gotta have the goods to show that you can make the noise.
The 7.4L casting ID mark on...
The 7.4L casting ID mark on the side of the block has little meaning since Hye Tech over-bored it another 0.060-inch. With the 4.25-inch-stroke crank, its new displacement is now 8.1L (496 cid).
Building ItPutting together a stroker big-block like this one has become ridiculously easy, thanks to the large influx of affordable aftermarket parts today. When we started out, we first went to Hye Tech Performance and outlined our basic wants and desires for this engine, which was at least 700 hp and it had to run on pump gas. We also wanted the motor to sound mean and look as good as it could. And we didn't want to spend next year's salary on it. Sod Bogosian, owner of Hye Tech immediately went to work assembling a parts list for us.
Then it was a simple matter of getting on the phone and ordering the parts from Jeg's High Performance Warehouse. We've included a detailed list of the parts if you want to copy this engine on your own. We're not going to give you prices, because they can change from the time we write this to the time you've read it. But remember, reliable power at this level is not cheap. So don't think you'll get this thing built for under $10,000. That is, unless you already have a whole bunch of parts lying around which you can pick through to build your own street hunter.
This month we'll highlight the parts and some of the assembly work on the engine. Then we'll detail the dyno testing in an upcoming issue.
 The Jeg's R-port aluminum...  The Jeg's R-port aluminum big-block J-Series heads feature 310cc intake runners, 119cc chambers, and 2.25/1.88 stainless valves. They also come with roller-ready springs that can take up to 0.750-lift. |  Hye-Tech Performance wanted...  Hye-Tech Performance wanted to gain some airflow from the heads and did some minor port-match work. See the accompanying chart for flow bench results. |  The kidney bean shaped chambers...  The kidney bean shaped chambers and stainless valves in the Jeg's heads promote swirl and combustion. The longer than stock valves also require custom-length pushrods. |