GMP 1987 Buick

The 1987 Buick GNX was GM's fastest production sedan ever and remains among Detroit's quickest and most collectible vehicles of all time. It was produced to commemorate the final production run of the Buick Grand National. It's a little bolder in appearance and it had considerable mechanical improvements over its predecessor such as the ASC/McLaren suspension. 1987 was the only production year for the GNX with 547 automobiles manufactured, all optioned identically with a serialized plaque on the dash.

In collaboration with ASC/McLaren, Buick Grand Nationals were assembled at the Buick assembly line and brought to ASC for conversion. The 547 were allocated to dealerships based on their previous sales of the Grand Nationals. The word was out that the GNX was even faster than the Grand National so dealerships enjoyed marking them up well above their sticker price of $29,290. Some famous customers were Burt Reynolds, Reggie Jackson, and Charles Schwab.

ASC/McLaren increased speed and agility by improving the traction and lightening the load. The front suspension remains exactly the same as the stock Buick of that time, however the rear axle is totally re-modified. The GNX has a ladder bar/panhard rod rear suspension instead of the standard control arm 4-link found on all other G-bodies. GMP captured the ASC/McLaren suspension perfectly in their recreation of this stunning piece.

Another key improvement to handling and acceleration was to reduce weight. The GNX was equipped with aluminum rear brake drums and bumper inserts, which were good for a 40 lb weight loss compared to the standard production Buick. Also, the GNX utilized a lighter wheel combination instead of the steel 15"x7" Grand National wheels. The wheels on the GNX were replaced with a lighter 16-inch black "honeycomb" alloys, which were 2-piece welded construction having Good Year tires VR50 245/50/16 mounted up front and 255/50/16 on the rear giving the car a distinctive stance. Again captured perfectly by the GMP replica.

Upon popping the hood one will view a 3.8 engine. There was no difference internally between the 3.8-liter SFI Grand National engine and the GNX engine. Initially, there were plans to perform standard performance tricks, such as blueprinting the engine during assembly. However, tests proved this was an unnecessary step that wasn't required to achieve their goal. Therefore these additional tweaks were deemed impractical after review by management.

For example, a port/polish job was considered as a tweak on the GNX. The problem with this idea was it would require a complete teardown of a brand new engine. Why? Grand Nationals were delivered intact to ASC for all conversions. The process of removing the upper half of the engine and performing the machine work could easily be 50 hours of labor. Then there was the risk of failure caused by improper re-assembly of the engine. Management upon reviewing the proposed tweak decided there was just too much risk to undertake such an aggressive enhancement not to mention the cost therefore it was scrubbed.

McLaren on the other hand had some ideas of his own on how to tweak out the GNX specifying the following improvements.

A modified T-3 turbo was used with a ceramic impeller wheel, which provides a lighter rotating assembly for quick spool-up and more efficient operation at a higher boost. However, this led to concerns that the rough factory wire-feed header welds might dislodge under stress and shatter the ceramic turbine wheel. McLaren addressed this fear with a contamination trap on the turbine wheel, which was unique to the GNX.

The GNX intercooler has a slightly higher fin per area count, making it a little more efficient at removing heat from the air charge. Each intercooler contains a label from ASC/McLaren and an individual serial number. The GMP replica contains an awesome engine compartment loaded with detail but I could not find the ASC/McLaren label. There was however a GNX label visible on the turbo I will assume in place of the ASC/McLaren? Not to split hairs we do have to consider licensing cost and other factors that would result in the missing label.

Another interesting fact on the GNX was the emission control label, located on the air conditioner box, was applied over the factory Grand National label. The only difference between the two was the manufacturer on the GNX was listed as ASC not Buick. It's unclear whether this was a requirement or to circumvent emission concern with the more powerful motor? This label is missing also from the GMP replica. Again no big deal since these labels are so small making them nearly impossible to read.

The exterior of the GNX looks a bit more aggressive than the Grand National. The functional engine louver vents located on the top rear of both front fenders were painted flat black to contrast against the glossy black body color. Fender flares were also installed to accommodate the larger tires giving the automobile a broader looking stance. Both features are captured perfectly on the GMP GNX Model.

There are two GNX emblems located on the exterior of the GNX they are located on the trunk and front grille. Originally five emblems were planned two GNX emblems and three 3.8 SFI Turbo emblems. The instrument panel was completely redesigned for the GNX. The GNX sports 6 Stewart Warner analog gauges. The speedometer and tachometer are 3-1/2", while the fuel, oil, temp, and boost are 2-1/4. The gauges on the GMP model leave little to be desired in my view. The gauges have a toy car appearance, which detracts from an otherwise beautiful replica. The ASC McLaren sticker is located on the driver's door near the GVW sticker on the GMP model making for a nice touch.

Overall the GMP 1987 GNX is a worthy piece to add to your collection. I found the fit and finish to be outstanding I love the stance of this replica along with the extensive engine detail along with the ladder bar suspension captured perfectly by GMP. I don’t like the gauge cluster at all taking issue with its toy like appearance. Would that in it self prevent me from purchasing this replica? No. I consider this model a must have for the muscle car collector.