The SS 496 Project Page 1
There's an old saying that still gets tossed around fairly often:
"There's no replacement for displacement."
Actually, there is a replacement for displacement. It's called "technology." However, like most everything else in life, technology comes at a price, and it's seldom cheap.
In the automotive world, technology has progressed by leaps and bounds over the last decade or so, providing enthusiasts with seemingly limitless choices when it comes to engine components such as rotating assemblies, camshafts and valvetrain components, and perhaps most importantly, cylinder heads and induction systems. The latest and greatest state-of-the-art aftermarket cylinder heads and that monster roller cam kit are never any further than a phone call or an online shopping cart away.
There's no denying that often these components can make a dramatic difference in power output. I've seen a swap to aftermarket cylinder heads knock a full second off of a car's e.t. with no other changes. It's hard to argue with those kind of results. These parts certainly have their place.
However, all too often I see enthusiasts getting duped into believing that they need these parts to achieve what really often amount to relatively modest performance goals, when more often than not, factory components are more than adequate to do the job. I credit this phenomenon to a combination of advertising bombardment and the "eye candy" factor. Nothing draws a crowd better than the latest aftermarket aluminum heads or the latest billet gee-gaws when the hood gets popped at the local choke & puke burger joint. And we can't forget (no matter how hard we might try) the guy on the saturday morning automotive high performance tv shows screaming at the top of his lungs how you simply can not live another day without the latest billet gizmos piled under your hood.
Advertising at its finest.
If this is what you're after, you might as well stop reading right here.
Fact of the matter is, the money you might otherwise spend on all the latest trick aftermarket goodies can likely be spent much more productively elsewhere for all but the wildest street-bound rides. Why spend your hard-earned money on the latest and greatest aftermarket parts if they're not really needed?
As such, I have absolutely no intention of trying to convince you that you need all the latest gadgets and gizmos in the front of your favorite speed shop catalog to build something that runs great on the street and at the track--quite the contrary; you don't need every trick aftermarket component you can get your hands on under your hood to build a great running car--no matter how much the guy on tv tries to convince you otherwise.
Which brings me to the focus of this 496 build. I wanted to take advantage of some new school technology and combine it with some proven old school technology to build a strong running engine that's still based mostly on OEM components. As I'm a firm believer in cubic inches, I decided to build a "new-old school" 454 thats based upon the legendary LS6, but takes advantage of a little modern technology with a stroker crank, better reciprocating components, as well as a little more aggressive camshaft timing. Still, there's nothing even remotely "trick" about this engine--actually, in comparison with current trends, this engine is decidedly UN-trick.
So why a 496 instead of a 427or 454 based engine?
As I said, I'm a believer in cubic inches (up to a practical limit). The core engine I started with had a thoroughly-worn cast crank that was already turned .030"-.030", so it obviously wasn't going to go back into service inside this engine. Since it didn't cost any more to build a 496 than it would have to build a 427 or 454 based engine (including the cost of a new aftermarket mid-level crankshaft), the choice was obvious.
So what's the goal?
First and foremost, to use as many OEM parts as possible in an attempt to keep costs within a reasonable range, and to retain as much of an OEM appearance as possible. The ultimate objective will be to build a relatively low-revving (6500 rpm) engine that will take my 4-speed `67 Chevelle project deep into the 11 second zone on premium pump gas in full street trim, all while maintaining acceptable street manners and solid reliability.
Accomplishing this goal will require spending money only where it will do the most good, which means (in no particular order); No aluminum heads. No roller cams. A simple flat tappet cam will get the job done here. (I'm no longer a proponent of running a solid roller cam on the street. More on that later) Not even a set of roller rocker arms. No single plane intakes. A factory aluminum dual plane intake will suffice. No monster high-dollar carburetor. A factory 855 cfm vacuum secondary Holley will be pressed into service. Yes, you read that right, an OEM vacuum secondary carb. No double pumpers. No Dominators. Not even a milled choke tower. And again, it all has to look factory. The only obvious exception will be a set of headers.
The engine will see dyno time at the facilities of the legendary "Ohio George" Montgomery's speed shop in Dayton, Ohio. Before I go any further, I'll tell you up-front--don't expect some bogus, over-inflated "car magazine" dyno numbers. I use George's facility for several reasons, not the least of which is the fact that his dyno is very conservative--or in George's own words, "stingy." There are several other local dyno facilities that I could've just as easily used which would've likely produced much more "magazine-friendly" power figures, but what's the point? I have no desire to publish bogus dyno numbers, and I'm not the one who's trying to get you to buy every "trick-of-the-week" part they can to keep my advertisers happy.
My power goal is somewhere around 525 horsepower and similar torque figures, all in full street trim through the same mufflers that will be used on the car. To put those numbers into perspective, consider that a well-tuned 454 LS6 running through open headers should normally make around 440-460 HP and 480-ish ft.lbs of torque on a realistic dyno. I'm only looking for roughly 75 horsepower on top of that just by the added cubes, a slightly better factory carb and intake, and a little more cam timing. I don't necessarily expect to attain those numbers right off the bat, and a second trip to the dyno is already planned after some minor revisions to the original combination. Also note that dyno testing will be conducted in a "worst-to-best configuration" manner; as I have several modifications planned to achieve the final combination, I need to start out with certain things that I know will not work, then progress my way to the final combination. Otherwise I would be unnecessarily repeating several assembly/dis-assembly steps. The biggest modifications from the original combination will be some minor cylinder head and intake manifold porting, and I may try a few different cams in it as well. Once that's done the engine will go back to the dyno for follow-up pulls to see what the modifications were actually worth.
Now that that's out of the way, follow along with the build and we'll see what kind of noise this thing can make on the dyno when it's all said and done. It will be a while before the car itself is track ready, but once it is, we'll find out what this project is truly capable of.