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1974 Pontiac Trans Am 455 - Firebird Family Affair


As deceiving as it might appear, this isn't your ordinary 250hp 455 four-barrel mill from 1974.
As deceiving as it might appear, this isn't your ordinary 250hp 455 four-barrel mill from 1974.

The correct '74 YW-code block was bored 0.040 inch to a total of 4.191, and the nodular-iron crankshaft retains its original 4.21-inch stroke. Total displacement equates to 465 ci. Cylinders were filled with Speed Pro forged-aluminum pistons, Sealed Power moly rings, and Eagle H-beam forged-steel connecting rods. The entire rotating assembly was balanced and rides on Federal Mogul main and Clevite rod bearings. A 60-psi Melling oil pump within the stock oil pan pressurizes the lubrication system.

To remain F.A.S.T.-class legal, CVMS massaged a pair of 4X cylinder heads for Jay's 455. In addition to milling the heads to meet Jay's target compression-ratio range of 10.0:1, the company completely rebuilt the castings and performed a competition valve job including new 2.11/1.77-inch valves. The intake ports were enlarged to R/A IV-size, and port work increased the intake and exhaust airflow capacity to 257/215-cfm at 28 inches, respectively. CVMS also port-matched a correct No. 495106 cast-iron intake manifold with EGR.

A Comp Cams hydraulic-roller camshaft featuring 236/242 degrees duration at 0.050 inch and a 110-degree lobe separation angle opens the valves to a gross valve lift of 0.552/0.562 inch when combined with the 1.65:1-ratio Harland Sharp roller rocker arms. On the rear of the camshaft is a points-type distributor triggered by a Crane XR1 conversion kit with a rev-limiter setting of 5,800 rpm. The stock coil initiates spark, and the stock-replacement plug wires transfer the current to a set of AC R45TS spark plugs. Total timing is set at 34-degrees BTDC, which is achieved by 2,800 rpm.

The correct No. 7044262 Quadrajet modified by Cliff's Q-Jet contains 0.069-inch primary jets, 0.042-inch-diameter primary metering rods, and 0.040-inch secondary metering rods. A stock-replacement mechanical AC fuel pump acts as a return-style regulator for the Mallory Comp 110-series electric pump that supplies fuel to the hungry mill through the stock fuel lines. A replacement K&N air filter residing within the stock air-cleaner assembly cleanses the cool air that's drawn through the modified Shaker scoop.

Unlike most enthusiasts who seek maximum output, Jay decided to forego tubular headers and even Ram Air-style exhaust manifolds. Instead he chose to reuse the original No. 490142 and 490143 log-style exhaust manifolds to comply with F.A.S.T.-class rules. The castings were port-matched, and the collector flanges were enlarged to a diameter of 2.25 inches. They mate to a 2.5-inch aluminized exhaust system from Pypes Performance Exhaust of Hatfield, Pennsylvania, that includes an X-type crossover, a transverse-mounted DynoMax Ultra Flo SS muffler, and reproduction chrome exhaust extensions.

Behind the high-performance mill is an original cast-iron flywheel with an 11-inch Hayes street/strip clutch. Coupled to this is a Borg-Warner Super T10 manual transmission that was rebuilt by Eric Babin of Marietta Auto Specialists in Marietta, Georgia. The original 8.5-inch GM 10-bolt rear axle with limited-slip differential, which contained its original 3.08:1 gear set, will soon house a 3.42:1 unit.


The T/A's suspension consists of many stock components, including its original 1.25-inch front and 0.812-inch rear stabilizer bars and rear leaf springs that are now clamped just ahead of the axle tubes. Front coil springs are from Moroso, and the front shocks are Competition Engineering 90/10 drag-racing units. Rear shocks are stock-replacement Delco pieces. Competition Engineering bolt-in subframe connectors help dampen road imperfections and improve body rigidity.

A set of restored 15x7-inch Honeycomb wheels accented by N.O.S. trim rings and center caps are mounted onto the original front-disc/rear-drum brake system. And even through Jay's Trans Am was originally equipped with GR70x15 steel-belted radial tires, he chose a set of reproduction F60-15 Firestone Wide Oval bias-ply tires to maintain a period-correct look and still comply with F.A.S.T.-class rules.

Since the Trans Am's completion in early 2005, Jay and Nicole have amassed a small collection of trophies, many of which are Best in Class awards. Included among them is HPP's coveted Editor's Choice Award, which was presented to Jay and his 18-year-old son, Jack, at the 2006 Pontiacs In The Park event in Petersburg, Virginia, covered elsewhere in this issue ("PY Pontiacs in the Park," page 32). This Firebird's success, however, is not limited to the show field.

Jay DeLaigle received his Trans Am in May 1985, as shown, at the young age of 18 as a high school graduation gift from his father and has retained a lead foot ever since. Note the burnout marks at top left.
Jay DeLaigle received his Trans Am in May 1985, as shown, at the young age of 18 as a high school graduation gift from his father and has retained a lead foot ever since. Note the burnout marks at top left.

The 455 engine in the stealthy Trans Am cranked out 380 hp at 5,300 rpm and 464 lb-ft of torque at 3,500 rpm as measured the rear wheels. And even with a portly race weight of 4,150 pounds, the car owns a present quarter-mile best of 13.20 seconds at a trap speed of 108.90 mph in the F.A.S.T.-class event at Martin, Michigan, in June 2006. With a best 60-foot time of 2.17 seconds with the F60-15 Firestones, Jay hopes that with more power, better traction, a little tuning, and more seat time his Trans Am can break into the 12s.

How does Jay feel about his T/A? "I have always been attracted to Second-Gen T/As of all types. But I really like how few '74 455 cars are left, especially in Admiralty Blue. It seems that no one brings the base 455 cars back to the level that the SD-455s are. But the car isn't really a dedicated F.A.S.T.-class racer. It's legal if I choose to enter another F.A.S.T.-class event in the future though."

Jay's Admiralty Blue T/A isn't the only Second-Gen Firebird currently in the DeLaigle household. Nicole has a Buccaneer Red '74 Trans Am with a 400ci engine and automatic transmission that she calls her own. With a totally stock-appearing '74 Trans Am with 12-second potential and a wife like Nicole, it sounds like Jay has found the right combination in a couple different ways. Now that's what we call a Firebird family affair!

About the Restoration


During the restoration, the Firebird's subframe was removed and coated in black PPG primer.
During the restoration, the Firebird's subframe was removed and coated in black PPG primer.
The front suspension was also rebuilt while the body was disassembled. Moroso drag springs and Competition Engineering drag shocks were employed to help the car transfer weight during a hard launch.
The front suspension was also rebuilt while the body was disassembled. Moroso drag springs and Competition Engineering drag shocks were employed to help the car transfer weight during a hard launch.
Shannon Born of Street Machines and More stripped the T/A's body down to bare metal and reapplied three coats of PPG Admiralty Blue followed by two coats of PPG clear.
Shannon Born of Street Machines and More stripped the T/A's body down to bare metal and reapplied three coats of PPG Admiralty Blue followed by two coats of PPG clear.

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