1966 421 Tri-Power Bonneville Convertible Interior Restoration

Special attention was paid to every detail in the engine compartment, from the correct foam air-cleaner elements and reproduction air-cleaner lids, sourced from Ames Performance, to the Packard spark-plug wire set, the smallest clip on the carburetors, and everything in between.

Interior D'eleganceUndeniably one of the most luxurious and sporty cockpits to ever grace a production-based automobile, the Bonneville features a host of amenities. As a result of the elements invading through the previous owners' torn top, the inter-ior was completely stripped to return the cabin to its once lofty position among the elite, Ken determining what could be purchased versus restored. As the popularity of full-size offerings has always been lower than the intermediates, parts were scarce. After removing the dash and all interior panels, Dash Specialists of Medford, Oregon, restored the mile-long dashpad, while SMS Interiors of Portland restored the interior panels.

Replacement real wood veneer was purchased, and the owner painstakingly removed each dash and console insert, then cut, sanded, and stained all the replacement wood before expertly hand-fitting the panels. A replacement carpet was sourced from Ames Performance, and Don Vincent of Lorain, Ohio, had the task of recovering the seats in black leather and installing a replacement black convertible top.

421 Tri-Power EquippedThe original YJ-code 356-horse 421 Tri-Power engine only had a bit over 30,000 miles on the odometer but was sorely in need of a rebuild. Once the engine was extracted and disassembled, the block was boiled and checked for cracks, and the cylinders were measured to determine if an over-boring was required. As a testament to the stoutness of the four-bolt block, all that was required was a hone to rejuvenate the cylinder finish. The stock crank was freshened with a light polishing of the journals and installed with new bearings. A set of standard-bore TRW forged pistons (with chrome-moly rings) on the factory cast rods were carefully fitted to the engine. An N.O.S. oil pump was installed, and the bottom end was buttoned up with the stock oil pan.

Custom Chrome in Grafton, Ohio, restored the headlight bezels, while the owner returned the stainless steel windshield trim and cowl cover to their factory brilliance. Reproduction mirrors were sourced from Ames Performance, while Keystone Plating of Cleveland, Ohio, artfully applied a triple-chrome plating to the massive bumpers.

Reused, the original code 093 heads with 1.92/1.66 valves were subsequently replaced with restored castings by Larry Long of Arrowhead Performance in Berea, Ohio. Although the original castings were fine, the replacements' "093" head markings were clearer and made it easier for enthusiasts and judges alike to authenticate the 421 Tri-Power. A stock 067 cam with 273/289 degrees duration and .410/.413 lift was employed with a fresh set of lifters and stock pushrods to actuate the valvetrain via 1.50 rockers.

Originally rebuilt to factory specs by the owner, the stock Tri-Power carbs were rebuilt and replated by Craig Woodward of Youngstown, Ohio. The stock intake manifold was cleaned and port-matched prior to installation, and a factory Delco ignition system remains.

Cast-iron log-style exhaust manifolds were sandblasted and treated to a high-heat manifold coating by Eastwood, and a Walker factory replacement exhaust featuring 2-inch diameter pipes, dual mufflers, resonators, and tailpipes provide the Bonneville's growl.

An N.O.S. transmission rebuild kit replaced the clutches and seals in the Turbo 400, while a B&M shift kit was utilized to provide firmer shifts. A stock replacement torque converter was employed, and the driveshaft was rebalanced and fitted with heavy-duty U-joints.

The interior is luxurious and tastefully executed. A full-length lockable console separates deeply bolstered Strato bucket seats shod in leather. The rear speaker is artfully framed by a double-chrome faceplate with a Pontiac crest in the center separating the rear-seat passengers.

The factory 10-bolt Safe-T-Track differential with a 2.93 gear set was disassembled and cleaned. After replacing the clutches and putting in new bearings and seals, the rear was set up again.

Chassis And SuspensionFollowing careful documentation of all factory markings, the inner fender liners were extracted so that the core support, front frame, and firewall could be restored. After taking the surfaces down to bare metal and priming them, the chassis and firewall were repainted with Dupont Centari enamel with a flattening agent to match the factory chassis black.

A Southern car all it's life, the red clay of the Carolinas did a remarkable job preserving the integrity of the undercarriage from rust and corrosion. "A frame-off restoration was unnecessary but the entire suspension and undercarriage were restored to factory specifications," Ken said.