*All 1975-79 X-cars are front steer, with a revised subframe similar to the one on the 1970-81 Camaro/Firebird.  Almost every front end component interchange (e.g steering knuckles, A-frames, steering components) between the second generation F-car and late X-car.

*There are several generation gaps between the last generation X-cars, and several names have came up.  3rd, 4th (some people refer to 1973/74s as a separate generation), and 5th Generations are common references, but I prefer to stick with the third generation, because of the chassis lineage that separate 1962-67s and 1968-74s.  The December 1985 issue of Hot Rod refers to the second and third generation X-cars as 1968-74 and 1975-79.  (A majority of X-car enthusiasts refer to the late X-car as a 4th Generation, which has been compiled from the Nova listserv.) The other generation nomenclatures (this is confusing) had to do with the bodystyle.  A majority of people consider 1966/67 Chevy IIs as a separate generation, since the body and interior are different than the earlier 1962-65s (Super Chevy, June 1995).  The 1973/74 shared the same body with the earlier 1968-72s (same interior as 68-72 - revised sheetmetal e.g. trunk floor, taillight panel, bumpers), but the difference is the rear valence, large battering-ram bumpers, and wider quarter windows.

Note:  This debate is an ongoing issue, in which the vast majority of the Nova listserv refer to the X-car with 4 generations via consensus - much similar to the Chevrolet Monte Carlo - the Monte Carlo has six generations.  This has been based on the June 1995 issue of Super Chevy.  Not too many people on the Nova listserv will have the December 1985 issue of Hot Rod, but if anyone does, check out the 1968-79 X-car section.

*There are few aftermarket companies that exist for 1975-79 X-cars (J & W Nova Parts, Classic Industries), since parts are hard to locate, especially the body panels.  The body panels that are advertised in some resto catalogs are offshore stampings, except for a few pieces like floor boards and lower rocker panels (USA made).  From what I know, Classic Industries and J & W Nova Parts cater to post-1974 vehicles, and the only items that are available for a resto include shop manuals, various decals, and carpet sets.

NOTE:  This has been a problem for many years now, since the 1975-79 X-car have been forgotten or overlooked.  The downside of the 1975-79 X-car is the low collectability status (e.g. low resale value), but this generation of X-cars are reaching their silver anniversary.  This generation of X-cars have been treated like second-class Corvairs for many years now, since they are originally smogged from the factory.  The automotive aftermarket have ignored the demands for parts availability, and one way to combat this is to write to the aftermarket companies like Classic Industries and Year One, or better yet, GM Restoration Parts. Parts for the 1975-79 X-car are becoming harder to locate, and the only way to procure parts is to find NOS items, procure a parts car and use whatever is needed, or fabricate the component in question.  From my personal experience, I have had an A/C hose fabricated, since GM had discontinued the A/C hose assembly.  Remember, the late X-car is currently being treated like an AMC product, since there are no parts distributors available.  Here's the pic of the A/C hose:

*The emphasis on safety was one of the concerns in the 1970s, in which a lot of popular bodystyles like the hardtop and convertible were being discontinued and/or phased out.  Some people would blame Ralph Nader's book Unsafe At Any Speed, in which ex post facto regulations, enacted since the mid 1960s, forced the DOT to emphasize on safety issues, which include rollovers and energy-absorbing bumpers.  The DOT was emphasizing on rollover standards, and this brought an end to the traditional bodystyles that have dominated the automotive market for years.  That's why the 1975-79 2-door X-cars had fixed quarter windows and thick B-pillars, in which rollover safety was of mere importance.  Also, the fixed windows were another factor in which spending costs are reduced, which was a common practice with GM of the disco decade.  This is why the late X-car is more similar to a rebodied 1973-77 A-car Colonnade coupe with side vents.  Another trivial issue is that the pre-1973 bodystyle (which dates from 1968-72) remained the same in Argentina (unfortunately, production ended in 1978), because the safety laws weren't a problem at all.

*The door hinges on the 1975-79 X-car are welded (another spending reduction method to lower $$$), unlike other GM vehicles that have bolt-on door hinges.  Hinge replacement is a pain, since the hinge section that attaches to the door can be bolted on.  The other section, located below the A-pillar, will have to be welded to the body, since the hinge section cannot be bolted to the body.  This include other GMs like the H-car, Chevrolet S10/GMC S15/Sonoma (includes Blazer/Jimmy) pickups, and 1988-present Chevrolet/GMC pickups and SUVs.  Look down below on what weld-on hinges look like:

*The taillights on the base 1975-79 Nova (except the 1977-79 Concours/Cuatom) have a lineage to a Ford classic, in which the rows are stacked.  The Nova taillights are stacked horizontally, as opposed to the vertical layout on the 1964 1/2 -- 1966 Mustang.

*The rear track width was widened in 1968, in which a 60.5" rearend (from axle flange -axle flange) was used.  A 1968-74 style rearend will fit the late X-car (some 1975-79 X-cars will have the GM 7.5" rearend), even the aftermarket Ford 9-inch housings from Moser or Currie Enterprises.  The rearend from a 1967-70 Mustang/Cougar will bolt in, but the housing is a little lighter.  Click on the underlined link for axle codes and gear ratios.

*The later X-cars came standard with 14 inch rims and tires.  It's possible to fit 15 inch rims and larger tires.  Click here for the link.

*Since the late X-car was oriented toward luxury, rather than performance, another trend transcended, in which the late X-car served as a testbed for law enforcement duty.  In 1976, the Los Angeles County Sheriff's Department purchased 222 1976 Novas, which marked the first time that a compact was used for law enforcement purposes.  Nova 9C1s were produced between 1976 and 1978, but the police package was not carried on into the 1979 model year (the police package was carried onto the Malibu until 1983).  This is related to the retooling of the X-car line in early 1979 (production of the RWD X-car ceased on December 22, 1978), in which the FWD versions (commonly known as the Chevrolet Citation) were in pre-production as 1980 models.

Unfortunately, the 4th generation X-car was axed in 1985, because of poor sales.  (The 1980-85 X-car is of no relation to the "real" X-car, since the later X-car is FWD.)  Sadly enough, the RWD compact (which includes the X-car, AMC Hornet/Concord, Dodge Aspen/Plymouth Volare and the Ford Granada/Mercury Monarch) became a shadow of itself in the late 1970s and early 1980s, in which modern tech advances (like electronic feedback carbs and FWD) and CAFE mandates (for 1978 and newer vehicles) ended the reign of the RWD compact.  Another thing that ended the RWD compacts is that Detroit downsized the full and mid-size vehicles, and the "downsized" mid-size vehicles made the RWD compact redundant.  The "Jenny Craig" era (an era in which production vehicles were downsized to meet CAFE requirements) was a dead blow to the automotive industry in the late 1970s, because of the 1973/74 and 1979 energy crises.  FWD and downsizing (along with 4-bangers and sixes) was theorized as a way to build fuel efficient vehicles, and the original purpose was that these cars were regular production models that have been based upon the fear that a gallon of gasoline would have sold for $3 a gallon.

*The SS option, common to Chevrolets, remained with the Nova as an option since 1968.  The production #s vary, but the final year of the SS (1976) was deja vu when the six-cylinder 250 was the base powerplant, which wasn't seen since 1963.  The marque SS (along with GTO, GSX, and 442) was mud with the public after 1972, when the traditional musclecar was a memory, and taboo throughout the disco decade.  To reiterate this, RPO Z26, which was the SS option, became the option code for the Rally Nova from 1977 onwards.  This trend is similar to the rebadging of the Chevelle SS as the Laguna S-3 for 1974, in which the marques associated with performance musclecars didn't mix with the trends of the post-1972 automotive genre.

Oldsmobile marketed an Omega SX/4 option from ?1977-79, but this was just a vinyl graphics "appearance" option like the 1973-80 442.

*The Cadillac Seville of 1976-79 vintage is a distant cousin of the X-car, which is known as the K-body.  The only difference is that the wheelbase is longer (3 inches), and 4-wheel disc brakes were standard (only for 1977-79 models). Oldsmobile V8s (a fuel injected 350) and THM400s were standard as the base powertrain.  The basic setup is similar to the X and F-cars (which consisted of a unibody and a separate subframe).

In reality, the first generation Seville was in fact, a rebodied GM X-car (Cadillac engineers wanted to use the German Opel Diplomat as the platform to build the first Seville - the engineers vetoed the proposal and used the X-car since it was the only viable platform available at the time) - both the front subframe, rear axle housing (exc. for the pinion yoke) and trunk floor pan are the only components which are shared with the 1975-79 X-car.  Some Seville-exclusive components (rear axleshafts, 12" disc brakes on 77-79 models, rear disc brakes) do interchange with the 75-79 X-car and second generation F-car - the 12 inch disc brake spindles for 78 and 79 Sevilles will accept the Camaro 1LE rotors!

Also, the stock Seville disc rotors and axleshafts (along with brake drums from an Astro/Safari minivan) are usually sought-after for use with dirt-track racers since the bolt pattern is 5 x 5 - a set of 8" wide 73-91 Chevrolet/GMC truck rally rims are usually seen on dirt track 75-79 X-cars.

1976 Sevilles (including those manufactured between April and September 1975) will have a 5 x 4.75 bolt pattern - this was the only Cadillac which had a Chevrolet bolt pattern for one year only.  One would notice that the rear drums used on a 76 Seville was lifted from a mid-1970s A-body station wagon - this was the same drum assembly used with the Nova 9C1 police option.

*The base motor in the late X-car has always been the post-stovebolt Chevrolet straight 6, which dates back to 1962.  1975 was the first year that the 250 had the integrated cylinder head and intake, like the 6 cylinder Ford that are of the 170/200/250 family.  Buick X-cars (Omegas from 1976-79) differ in the powertrain department, in which their 231 (3.8L) was their base powerplant.  (Buick sold the patent rights to the 225 V6 to Kaiser-Jeep in 1967, and had to purchase the rights from AMC, Jeep's parent company since 1970.) The optional V8s vary, but in some cases, there might be a crossbreed (e.g. Chevrolet-powered Buick Skylarks or Buick-powered Pontiac Venturas/Oldsmobile Omegas).  Cross-bred powertrains began in 1975 in several GM vehicle lines, beginning with the X and H-car (Monza/Vega) lines.  This event led to the lawsuits filed by vehicle owners, but these cases were settled out of court.

From 1977-79, the basic optional V8 is a Chevrolet 305, except for the Pontiac Ventura/Phoenix.  Like other disco decade classics, the engines were heavily smogged from the factory, to meet the EPA standards that have been mandated since 1971.  Still, with the smog devices, the regular production motors listed below did not meet the fuel economy standards, until the advent of the 1978 model year.  If the overdrive tranny and/or EFI was introduced in the late 1970s, there would be a different outcome, in which the RWD compacts (and other production vehicles) would have stayed around for another few more years.

The V8 motors differed, depending on the GM division:

*Since 1973, Chevrolet engine mounts now use the block bracket and sandwich cushion frame isolator (similar to 1970-later Pontiacs).  The sandwich cushions will accept both the 6 cylinder and small-block Chevrolet, as well as the big-block Chevrolet.  This makes swapping in a Chevrolet V8 (rat or mouse) simple, as long as the correct block brackets are used.  The block brackets are still available from GM or from a salvage yard.  A big block will bolt onto the cushions using the small block engine brackets, but this swap is illegal for emission-controled vehicles driven everyday on the street, since the Rat was not optioned from the factory. (Under EPA regulations, the motor must be the same year or newer than the vehicle.  Crate motors like the 454/502 H.O. are recommended for off-road use.)

*Installing bucket seats in a 1975-79 X-car is a total nightmare, and the factory bracketry is the hardest part of the installation.  GM Restoration Parts does not stock these parts yet, and here's a pic of a factory bucket seat car.

The pic above is a template where a 4 speed tranny hump is located - the hump is used in conjunction with a console.  Here's a link if anyone has ever seen a 75-79 tranny hump.  After 1974, a tranny hump was not used when a floor shifted automatic was optioned - the shifter was mounted to the floor in a similar fashion like the second generation F-car.  After 1974, manual-shifted GM X-cars are a rare find - here's a link in response to stick parts.