The Saturday-Night Buildup car really came alive with the addition of a set of L31 Vortec
The Saturday-Night Buildup car made a huge leap forward in performance at our most recent 11/42-mile, dirt-track oval race at Perris Auto Speedway in Perris, California.
Thanks to a set of GM Performance Parts Vortec heads (PN 12558060/see our Feb. '98 issue), a new camshaft from Comp Cams, new spark plug wires from Performance Distributors, and new race tires from McCreary, the car took on a whole new attitude. Actually, believe it or not, the complete head sells for less than the bare head (PN 12529093). Even if you didn't want the extra parts, you'd be better off purchasing complete heads and saving the valves, springs, and so fourth.
While we were more than very pleased with the performance of the stock crate engine, we wanted to bump it up a notch, similar to what a typical guy might do after a season of racing. The new parts were just what the doctor ordered.
We have done extensive before and after dyno testing at K&N Engineering's state-of-the-art chassis dyno to make sure we weren't skewed by seat-of-the-pants impressions. The new heads and cam were worth 45 hp at 5,250 rpm compared to the stock engine. This low-buck, rock-crusher-simple engine is now putting out 235 hp for about $2,600. Our original engine, complete with 1.6 rockers and shaved heads, put out 228 hp! And that's with about $500 worth of heads and cam-amazing.
We finally got the courage to lean out the Barry Grant 4412 two-barrel carburetor. We ended up going down three sizes to an 80 main jet. But then we noticed a jittery, erratic condition in the power curve above 4,000 rpm. K&N dyno operator James Psihramis suggested going up on the power valve size based on some testing done at the shop with a spec truck. We increased the power valve to a 35, and when all this jetting was done, the powerband was far smoother.
These numbers made us delirious. The scene at K&N's dyno reminded me of one of those infomercials-"I wouldn't have believed it if I hadn't seen it myself." It was truly a remarkable improvement for a very little amount of money and effort. So much for those hot dogs with all their fancy engines.
Did the car act differently at the track? Absolutely, 100 percent better. The engine was snappy (and we're still talking about a 9:1 compression ratio here) with a whole lot more power than it had at the previous race.
In our heat race, we flew through the pack to finish Third and transferred directly into the main event. We started the main in the 12th spot and ground our way up to Fourth Place with five laps remaining in the 30-lap race. Driver Bob Carpenter was just about to pass both the Second and Third Place cars to go into Second, when the caution came out.
The car was visibly faster than before and Carpenter even commented that his neck was getting strained from the cornering forces. While circulating around the track under caution, the car quit. We didn't know why until a day later when we discovered it had run out of gas! We had run only 20-lap mains in the past and didn't know we couldn't make it for 30 laps (there were a lot of cautions and even a red flag).
After the race, the car drew a crowd. One guy sneered that there was no way it had a crate motor in it. I told him I'd tear it down with him right there, and for every nonstock part he found (except for the solid lifters, Competition Cams camshaft, and Edelbrock intake manifold) I'd give him $1,000. The look on his face was great. "Are you serious?" he asked. "Damn straight," I told him. "It's those Vortec heads." When Circle Track first proposed using this engine, we thought there was no way it could run with the high-dollar race engines. But we have been happily surprised with the performance. Next season, we're shooting to win a race with this engine.
We like to arrive at the track early enough to get a decent pit spot. The car is always re
Readers who have been following along with the GM Performance Parts crate motor test know
Another factor in our upgrade was the addition of solid lifters. We've never used solid li
Yes, Virginia, we continued to use all the stock components in our crate engine. The heads
One key to using Vortec heads is you need an intake manifold that not only fits the new bo
Notice how our Phoenix Fire Systems halon bottle is mounted within easy reach of driver Bo