Here's what a dyno-ready $2,580,...
Here's what a dyno-ready $2,580, 506 hp engine can look like. Just because it's cheap, it doesn't have to look cheap. A lot of hard work cleaning up and painting used parts (including those fancy valve covers) goes a long way to making an engine look a lot more expensive.
For the budget-constrained racer (that's most of us) BC does not mean Before Christ. Instead, it means Buy Carefully. At the end of the day that is the key toward cheap power.
The intent here is to walk you through the logic and procedures to build a low-cost engine with some real hp. But, to address this issue of cheap power, I am also going to look at some of the logic in the rules that dictate the use of flat tappet cams instead of a roller cam that is so often seen as significantly more costly. As you will see, the key factors toward achieving 500 hp simply-and at minimal expense-are in selecting the right parts, especially in the head and cam departments. It takes a certain minimum amount of head airflow and a valvetrain to access that flow to get the job done. With that in mind let's see where we can go with this.
Back when the only roller cams were hi-buck aftermarket pieces, the roller cam got a reputation for being too costly for the typical Saturday night racer and, for that matter, NASCAR's top series. Yes-believe it or not-the original reason for a Cup car's flat tappet cam was to keep costs down. But for some 25 years Detroit had been building hydraulic roller cam V-8s by the millions-at a user friendly price
The near-zero wear bores on...
The near-zero wear bores on this block were cleaned up using a three-leg glaze buster. Cost to recondition and paint it as seen here-less than $50!
Go to the wrecking yard (maybe the politically correct term now is Auto Parts Recycling Yard) and you can pick up a late-model (1987 and newer) hydraulic roller-cammed, small-block 350 Chevy for about $500 or so. Let's deal with the issue that these are roller cam motors instead of the often dictated flat tappet cams and see where it takes us in terms of cost and power.
First, any engine we buy to race will have the stock cam swapped out for a race cam. If flat lifters are to be used, this means buying a cam and lifters. If the hydraulic rollers (which rarely wear out) are retained, then the cost of a set of lifters is eliminated. These days, the flat tappet race cam profile designs are pushed to the limit allowed by the metallurgy and unless strict break-in procedures are adhered to and top grade (read: more expensive) flat tappet oils are used, the cam and lifters will wipe out. When that happens, things start to look a lot less cheap.
Here are my thoughts on the subject. Let the engine have a roller cam so it can make about 500 or so hp and from there limit the advantage of any further power increase by specifying a tire that won't hook up with much more power. That should make a great ride for the driver and fast racing for the spectator. If that premise appeals to you, then here is how to build it cheap and have it last the season.
A stock late-model 350 piston...
A stock late-model 350 piston is shown at right versus a high performance aftermarket street piston. Note how much smaller the pistons rings are and how much smaller the ring belt is.
Back to our late-model, hydraulic roller-cammed 350 Chevy. Because these motors were fuel-injected, the piston/bore wear on most of them is low to non-existent, even if the unit has 150,000 miles on it. This means that the pistons can be re-used and the bores, when cleaned up with a deck plate hone job, inevitably end up with right around the best piston-to-wall clearance for a race motor (about 0.004 -0.005). But maybe the bores have so little wear they will clean up with a glaze buster (as in about 30 percent of the cases). You can buy a 3-leg honing stone glaze buster for $29 at NAPA and do the job at home.
The only potential problem here is that the dish volume of some stock pistons is a little on the large size for a decent CR - but that's a situation we will deal with shortly. At this point, with a new set of rings, the piston/bore situation can be brought to a decent race spec for about $200. Not only that but the rings on these late-model engines are a low-friction narrower wall design, and that's good for power. If you bought new aftermarket pistons, such a design would be a more costly upgrade.
These late-model motors inevitably have powder-forged metal rods. These are better by far than the old Pink hi-performance factory rods and, in my experience on just two motors, seem to deal with an average quarter-mile circle track race season.
Next on the agenda is the crank. Most of these motors will have a cast crank. While certainly not the No. 1 choice, we have not had any trouble with these as long as all the crank clearances are middle to top limit and an "as new" stock or good aftermarket crank damper is used. Usually the stock crank is good to go with no more than a journal polish. If you want to make a near-bulletproof but cheap upgrade here, then the Scat cast steel replacement crank (9-10526) is a good bet. It can be bought for under $190.
The powder-forged stock rod...
The powder-forged stock rod is a nice piece for a production item. If the engine is going to repeatedly see more than 7,000 rpm, it's time to consider a rod upgrade.
To get the stock crank to...
To get the stock crank to live under race conditions for a reasonable time, be sure to set the bearing/journal and end float clearances toward the wide end of the factory tolerances. Also, use only an "as new" factory damper or a performance aftermarket damper.
Here is a surge tray typical...
Here is a surge tray typical of many later-model 350s. It will work if the budget is exhausted, but an entry-level Moroso pan will show better oil control and three or four hp more.