Go to any drag strip anywhere the country and you’ll probably see at least one Buick Grand National streaking down the asphalt. But odds are pretty slim you’ll find one on a road racing circuit — unless, of course you live in the Great Lakes area.

NASA Great Lakes rookie racer Todd Davis has effectively built a racecar Buick never did, for competition in a series normally reserved for Camaros and Mustangs. But the rulebook didn’t say you couldn’t build a Buick, so why not?

“I wanted to build something a little bit different, I guess as you can tell,” Davis said. “I’ve always been a Buick head for whatever reason. I had a 1970 GS I built as a pro touring track car, and it was a lot of fun, but it was a nice car. I didn’t want to cut it up with a roll cage and all that. I have a street version of a Grand National, pretty stock. So I thought it would be wild and kind of crazy and fun to build one of those into a road racer, so I went ahead and did it.”

SN_1112_RacecarFeature_2

The first question Davis gets is whether it has the original turbocharged V6, and the answer is no. He bought the car, which is a real Grand National as a roller from a guy who had been building it as a drag car. When Davis got the car, it had no engine, no transmission, no interior and no hood.

Because Grand Nationals have been collectors items since they were new, he had been looking for a Regal. He didn’t want to cut up a real one, and he could add black paint and the domed hood and still get the look he wanted, but everything he could find in his area was rotten and rusty. Then he stumbled upon the drag car project someone else had lost interest in.

SN_1112_RacecarFeature_3

“I really did want to use a turbo Buick, and I know sometimes people are disappointed when they find out I don’t have the Buick motor in it, but the problem I had was that engine never came with a stick shift behind it,” Davis said, adding that he installed the GNX fender vents to pull heat out of the engine bay. “I would have had to do a lot of extra engineering. I know it’s possible, but I really wanted to get this thing on the racetrack before the second coming.”

SN_1112_RacecarFeature_5

To get a powertrain for the car, Davis sourced an LS1 V8 and T-56 six-speed transmission out of a wrecked Trans Am. The drivetrain had 35,000 miles on it, so he pulled it from the F-body Pontiac and dropped it into the Grand National, but that’s when Davis began to realize the scope of the project.

SN_1112_RacecarFeature_6 SN_1112_RacecarFeature_7

There was first a matter of installing a NASA-legal cage. The cage installed for drag racing wouldn’t pass tech, so he had to cut it out and start over. There was also a little bit of rust to repair. Then he had to make a manual transmission work in a GM body that never came with one. That meant adapting a reproduction clutch pedal from an early GM A-body, like a Chevelle or Cutlass, and getting it to work with a hydraulic system that came on the LS1 powertrain.

Believe it or not, no companies make headers specifically for installing an LS-style engine in a GM G-body, so Davis had to take lots of measurements and match them up with a header dimensions from a number of different manufacturers, a process he called “a ton of research.” Once he found a set that fit, he finished it off with a custom exhaust system he made himself.

Because of their turbocharged engines, Grand Nationals didn’t use vacuum-boosted power brakes. They used a system called a Powermaster, which boosted brake pressure electrically, and was wholly unsuited to road racing. Davis adapted a vacuum system from a regular Regal and guessed at the proper bore size for the master cylinder.

He adapted C5 Corvette spindles to the tubular control arms that attach to stock pickup points on the frame, which let him install big 14-inch rotors and Brembo calipers up front. He added a brake bias adjuster inside, and adapted the stock brake pedal to the new system.

He left the recirculating-ball steering system intact, but replaced all the components and added a quick-ratio steering gearbox. For suspension duties up front, he went with conventional springs and double adjustable shocks.

“In hindsight, I probably should have put coil overs on because it would let me adjust my ride height, but I didn’t realize the advantage of that going in,” Davis said.

At the rear, the suspension has been something of a work in progress. He left the stock axle in place, with its 3.42:1 ratio and clutch-pack differential, but added a Watts link to keep undue motion in check. For springs, Davis has been fighting to correct what he called a “crazy, undrivable loose” condition.

“Originally, I had pretty light springs on there,” he explained. “They were really only 175-pound springs. A lot of guys are running 400 and even higher in their rear rates their Camaros and Mustangs. I tried the 175s and dropped down to 150s and the “loose” was a little bit better, and then I dropped down to like 100-pound springs out of a Camaro, and it was even better. The last race I ran at Road America, I was laughing because I had saved the sloppy old worn out springs that came in the car and I put those back in and that was actually the best handling I had so far.”

The build took Davis a year and a half, and he missed the first half of the 2012 season as he was finishing the car. As any NASA racer knows, a racecar is never finished, and the same is true for Davis’ Buick. Though he is down on power compared with some of his competitors, Davis managed a couple of good finishes in 2012 and even captured a win in the second to the last race of the year. Over the winter, Davis plans to add power and remove some weight from 3,470-pound car.

SN_1112_RacecarFeature_8

“When I look back at it now, it feels very worth it,” he said with a laugh. “It’s funny because the car has fans. I don’t have fans, but the car has some fans. There were a couple of guys that came to the race at Autobahn and said, “Yeah, we heard this car was out here. We just came out here because we had to see it run around the track.”

Todd Davis’ 1987 AI Buick Grand National

Weight:

3,470 lbs. (for now)

Engine:

GM LS1, 295 rwhp

Suspension:

Front: tubular control arms, coil springs with double-adjustable shocks; Rear: stock beam axle with Watts link, sway bar delete and stock GM coil springs.

Tires:

275-35-R18, Toyo RA1

Brakes:

Front: Brembo 14-inch rotors and calipers;

Rear: 2004 Corvette discs and calipers

Data Acquisition:

Todd’s brain
SN_1112_RacecarFeature_4
Comments
Images courtesy of Todd Davis and Tom Hitzeman