In the past, I've made a request for all of you to send in anything, from images to hot tips. Well, they're coming in by the armful, and that's a great thing, so please keep them coming. This month was especially difficult to pick from, but every once in a while, you get one letter that just really stands out. In this case, a reader I had the opportunity to interact with some time back was nice enough to follow up on his killer small-block. As always, if you have something to say, let me know, and if we print it, I'll swap ya for CHP goodies. -HD
Letter Of The Month
Last May, I responded to your small- vs. big-block test with the dyno results for my relatively inexpensive 412-cid SBC (654 hp and 576 lb-ft, 475 lb-ft at 3,000 rpm). At that time, you expressed interest in my project, and I'd like to bring you up to date.
The engine went into my mid-engine hillclimb race car, a '68 McKee F5000. I consider 2007 a shakedown year, as I am still trying to get used to the surfeit of power. I competed in seven hillclimbs and generally finished in the top four. I suspect those placings will improve in the coming year, even though the old F5000 lacks the ground effects found on the top cars. I'm one of those stubborn anachronisms who still think they can win a finesse-handling event with more power.
The McKee's dry weight is just over 1,400 pounds. All that power goes through two Hoosier Oval Asphalt 16-inch slicks, and despite the sticky tires and decent antisquat rear suspension, I find that acceleration is a tricky thing on our narrow mountain courses and cold tires. I finally added a huge 5x5 sprint car wing to get some downforce for the rear tires and keep the front wheels on the ground during spirited acceleration up the more than 20 percent grades.
First and Second gears get me up to 95 mph in 3 seconds, although I am using just the primary side of the Dominator. At just about 100 mph in Third gear, there is enough downforce that I can feed in a lot of throttle, and once into Fourth, I can mash the pedal to the floor. Only two hills (Giant's Despair and Duryea) and my test track (NHIS) accomodate the Fourth-gear blasts. Fifth gear is good for just over 155 that I hope to try at both hills next year.
I was somewhat disturbed during the hard Third and Fourth gear charge to discover I would lose my visual acuity. Everything took on a gray hue, and detail became quite blurred. Keep in mind that unlike a dragstrip, a hillclimb is held on a regular public road with telephone poles, trees, boulders, walls, and people lining both sides. Sometimes it feels like skydiving down an elevator shaft. After several runs, I was able to consciously force my eyes to adjust, and things would come back into proper focus. A visit to my eye doctor confirmed that my experience was a normal reaction to abnormal acceleration in such close proximity to so many objects.
I must admit the ride has become addictive-I am hopelessly hooked on it. I am able to accelerate hard uphill in Third gear as low as 2,400 rpm and still average more than 630 hp between 6 and 7 grand. The engine's wide powerband makes the data academic, as most of the time I'm just trying to avoid wheelspin. It seems like I can instantly attain any speed I dare just by stepping down on the right pedal, without fussing with the gearshift.
The most interesting statistic is that in 2007 I used less than half the fuel I used in 2006. While a BSFC of 0.35 suggests a very efficient engine, I suspect the real reason for the economy is that I was afraid to use the throttle.
Next year, I should also be road-racing the car against other F5000s and Can-Am cars. I look forward to seeing how it stacks up against the latter's big-blocks.
Many thanks for the fantastic engine buildups in the latest issue of the magazine. As old and as jaded as I have become, I can always look forward to learning something new with each issue.