Detroit Speed Built 1965 Buick Riviera GS is Everything That it Should be and Nothing it Shouldn’t
By Brian Brennan – Photography By John Jackson
The 1965 Buick Riviera GS is one of the most coveted starting points for any hot rod. Now, to this add some creative thinking to improve on an already award-winning design and apply today’s advancements in powertrain and suspension and you drive away with the best of all.
The 1965 Buick Riviera GS is part of the first of eight generations. There were 34,586 Rivieras produced but only 3,354 carried the GS option. From here the Buick was thought of as both a muscle and a luxury car that could also be transformed into a remarkable custom. The Buick Riviera succeeded at everything a hot rodder wanted and this GS hit all the marks.
Jeff Mosing, of Austin, Texas, has spent a lifetime enjoying all kinds of cars, but we dare say that this 1965 Buick Riviera is one special example. It made its debut at the 2022 SEMA Show, next appeared at the Summit Racing Nationals in 2023, and made an appearance at the latest Goodguys Street Machine of the Year competition. It has also received the Bowler Performance Transmission Muscle Car pick at Goodguys.
While we are going to point out the high points on the myriad of modifications to the sheetmetal, powertrain, interior, and chassis, make sure to be on the lookout for individual build stories showing up in future issues of Modern Rodding to show what happened behind the scenes. As with any project of this size and caliber it takes a “town” to raise it. The building of this 1965 Buick Riviera did take place under roof at Detroit Speed in Mooresville, North Carolina. However, there are many who shared their craftsmanship to make the build happen. The fabricators on this project included Blake Tomlinson and Josh Smith, machinist Matt Haye, along with Michael Neighbors and Austin Moore, while final assembly and wiring was in the capable hands of Jason Eads.
The sheet metal retains the looks we have come to love on the 1965 Buick Riviera while undergoing a few tasteful modifications that “work.” What has become mandatory on any ’60s hot rod build—the bumpers, front and rear, were removed and reworked. In this case our ’65 had both its bumpers built from scratch while the rear roll pan was reshaped, rocker areas reworked, allowing for the peak-though exhaust and the lower quarter-panels to be reshaped. The Buick Riviera was debadged and the drip rails shaved. Interestingly the glass, while stock, was remounted but this time as a flush fit. The lighting, headlights, and taillights were custom machined, showing off the new front “clamshells” and the freshly minted tail light housings, lenses, and trim. The new front turn signals were crafted by a 3D printer while the exhaust features custom rings; a Detroit Speed hood ornament is now visible.
The bodywork and paint were performed at Detroit Speed with the use of PPG Ferrari Rosso Mugello Red as the selected color. (Rosso Mugello is Ferrari’s deep, almost maroon, red color. It was introduced on the 2004 Ferrari F430 and the 2007 Ferrari 599 GTO as well as on the 2019 Monza SP.) What brightwork there is was fittingly processed by Advanced Plating and beautifully accents the body lines and cleanly breaks up the bold color.
For the interior, let’s begin with the modified factory dashboard. The Buick Riviera has always been known for its impressive dash and center console and while it retains its distinctive look there are some noteworthy alterations. The dramatic instrumentation comes by way of Classic Instruments with its single left-mounted circular 160-mph speedo, a center-mounted small-diameter circular tach, and single right-mounted circular gauge with its center-mounted clock and the obligatory fuel, temp, volt, and oil instruments surrounding the timepiece. Getting all the wiring to handle the chores, which includes the Classic Instruments gauges and Vintage Air Gen IV AC System with upgraded dash controls, is the handiwork of Eads whose skills were seen on the American Autowire custom-built wiring system. Also, highly visible and eye appealing is the custom-machined two-spoke wooden wheel, with paddle shifters and machined in-house, that rests on top of the tilt ididit steering column. We have mentioned that the Riviera is also known as a luxury car and in keeping with that obligation is a pair of front Recaro bucket seats plus a pair of custom bucket seats in the rear with a center displayed “waterfall.” The tan leather is used to cover all the seating, panels, and so on, by Phil Cato of Cato’s Custom Upholstery of Salt Lake City. He also stitched up the headliner, which is made from Cattle Tan Suede as well as the dark brown carpeting. Note the trunk is equally as detailed and now acts as a home for the relocated Optima battery that’s mounted within a Detroit Speed relocation battery tray.
All of this is great but let’s face it, it’s the hustle underhood that makes a hot rod come to life. While there is nothing wrong with a vintage Buick Nailhead, many would say that’s exactly what should be there but not so for this ride. Delivered from Mast Motorsports is a Black Label LSX engine. The LS-based block comes by way of Chevrolet Performance, an LSX tall deck iron block equipped with Black Label aluminum heads. After the machining was handled by Mast Motorsports there was the ample use of ARP bolt, Diamond 12:1 pistons, and a Mast custom camshaft. The Nailhead-appearing valve covers are custom pieces machined by Greening Auto Company with the block painted in vintage Buick light blue. A single-plane Holley intake manifold is used along with a Holley EFI with a custom-fabricated air cleaner that’s reminiscent of the mid ’60s. The computer electronics are administered by a Holley Dominator system, along with GM coil packs, custom plug wires, and a YellowTop Optima battery. The slick-looking headers are made from 1-7/8-inch stainless that dump into Detroit Speed–fabricated 3-inch custom headers with Blackheart exhaust cutouts that then link to a pair of Hooker Blackheart mufflers. Other engine accessories include a Vintage Air Front Runner, GM starter, SPAL electric fan nestled within the factory appearing fan shroud (also machined at Detroit Speed), and a C&R oil cooler. Linked up to the 650-plus horsepower and 630-plus lb-ft of torque is a Bowler Performance 6L90E transmission with a Shiftworks shifter that maintains the original factory look and an Earl’s transmission cooler.
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The frame is based on a set of custom ’rails with a Detroit Speed hydroformed subframe with custom three-link using Detroit Speed Swivel-Link technology in back. The front is based on a Detroit Speed SLA with Detroit Speed drop spindles, a 1-1/4-inch front sway bar, double-adjustable JRi coilovers, and Detroit Speed rack-and-pinion steering. In the back a GearFX rear end is used based on a Ford 9 inch rear end with US Gear 3.50 ring-and-pinion and Moser axles. Bringing all this hot rod to a halt is a front/rear combination of Corvette ZR1 with Z06 package carbon-ceramic rotors and calipers plus a JRi ride height system and Bosch ABS. The wheel-and-tire combination is made up of Roadster Forgeline wheels measuring 19×8.5 and 20×10 then wrapped with Michelin Pilot Sport high-performance tires coming in at 265/35R19 and 295/35R20.
It may look like a 1965 Buick Riviera GS and it most assuredly will remind you of a bygone era, but once inside, once you twist the ignition key, and once you press down on the throttle there is no denying you have entered the era of the modern-day hot rod. MR
Click on this issue’s cover to see the enhanced digital version of The Ultimate Buick Riviera Build?