The Mercury Cyclone saga was started in 1964 with a 289-cid (4735-cc) 210-hp (156.5-kW) engine. When the '64 model was brought out, it was designed to look sporty. So it had a spoked steering wheel, bucket seats and some of the engine parts were chromed, as that was part of the style of early muscle cars.
For 1965 the engine was updated to the four-barrel carburetor version of the 289-cid unit, which strangely enough only produced 200-hp (149.1-kW). Also for the first time the '65 Cyclone had a few performance options, including a handling package, special fan and a "Power Transfer" rear axle.
Sculpturing, running the length of the car, was the major styling change for the '66 Cyclone, which was based on the Ford Fairlane's body. Also new engines were introduced in 1966. The 390-ci (6390-cc) Y code, with a two-barrel carburetor and 265-hp (197-kW); and the 390 H code, with a four-barrel carburetor and 275-hp (205-kW), were the engines in 1966. For the GT option, the 390-cid S code, with a four-barrel carburetor, 335-hp (249-kW) engine was available to those who opted for the 1966 Cyclone GT. The GT option also gave the car stripes, a fiberglass hood (bonnet) with scoops and several other performance options.
In 1967 the standard engine for the Cyclone was still the 390-cid (6390-cc), but with 15 fewer horses since it was quoted at 320-hp (238-kW). For some reason the Cyclone in 1966 and '67 didn't get the 427-cid (6989-cc) side-oiler that went into an amazingly standard Comet. Only badges told of the 410 horses (305-kW) under the hood (bonnet).
The 1968 model was named the fastest car of that year, because a '68 Cyclone ran a world record speed of 189.22 mph (304.5 kph) at Daytona. New engines were introduced for '68 as well. There were two versions of the 302-cid engine: the two-barrel carburettor code F, with 210-hp (156-kW); and the four-barrel carburetor code J with 230-hp (171-kW). There was also the 390-cid (6390-cc) engine with either: 265-hp (197-kW) two-barrel carburetor; or 335-hp (249-kW) four-barrel carburetor versions. Then, getting into the big guns: the 390-hp (290-kW) version of the 427-cid (6989-cc) side oiler engine. This engine was only available for a small part of the '68 model year, and was replaced by the cheaper 428-cid (6997-cc) with "only" 335-hp (249-kW).
A new model was added to the Mercury Cyclone line in 1969, the "CJ" or Cobra Jet. The Cyclone CJ had the 428-cid (7013-cc), 335-hp (249-kW) Cobra Jet engine, with or without Ram-Air. Strangely the Ram-Air version (Cobra Jet Ram) and the non-Ram-Air version (Cobra Jet) had no quoted difference in horse-power ratings. The '69 Cyclone had lots of engine options. There was the 429-cid (7030-cc) engine, which in the Marauder version had 360-hp (268-kW), with a four-barrel carburetor; a 220-hp (164-kW) version of the 302-cid (4948-cc); two versions of the 351-cid (5751-cc), a 250-hp (186-kW) and a 290-hp (216-kW); and there was the 320-hp (238-kW) version of the 390-cid (6390cc) engine. NASCAR was also on the agenda for '69, and the star for Mercury was the Cyclone Spoiler II. Five hundred was the minimum number of cars that had to be produced for the series. Mercury entered with 519 (503?) Spoiler IIs built. The street versions produced to get into NASCAR were not the same as the ones that were to race in it. One major difference was the engine powering them. The street version had a 351-cid (5751-cc) "Windsor" small block, but the race versions had the Boss 429-cid (7030-cc) unit, the same engine as the one in the Boss Mustang. The Mercury Cyclone CJ had the following enhancements over the Cyclone and Cyclone GT: it had a blacked-out grille; dual exhausts; 3:50:1 axle ratio; engine dress-up kit (chromed parts); hood (bonnet) stripes; and a competition handling package.
The CJ was dropped for 1970 after a restyle of the model rage. The Cyclone, Cyclone GT and the Cyclone Spoiler were the models left. There were three versions of the 351-cid V8 and four versions of the 429-cid engine.
The standard engine for the base Cyclone was the 429 cubic inch 4-barrel with dual exhaust that was rated at 360 hp SAE gross (likely 250 hp SAE net), which was the standard engine in the 1970 Mercury Marauder X-100 and was available in other full size models. It had a 575 cubic feet per minute (CFM) carburetor.
Optional engines for the Cyclone were: a 429 cubic inch 4-barrel with dual exhaust and ram air induction called the 429 CJ (Cobra Jet) that was rated at 370 hp SAE gross (likely 305 hp SAE net) and had a 700 CFM carburetor, a 429 cubic inch 4-barrel with dual exhaust and ram air induction called the 429 SCJ (Super Cobra Jet) that was rated at 375 hp SAE gross (likely 340 hp SAE net) and had a 780 CFM carburetor (it was only available with the Drag Pack option).
The Cyclone Spoiler was for the performance minded with front and rear spoilers, racing stripes that went from front to the rear of the car, hood (bonnet) scoop for ram air induction, racing mirrors and a competition package. The 429 Cobra Jet was the standard engine for the Cyclone Spoiler. Optional engines were the 429 Super Cobra Jet.
The standard engine for the Cyclone GT was a 351 cubic inch 2-barrel with single exhaust that was rated at 250 hp SAE gross (likely 175 hp SAE net) in both Cleveland and Windsor series. Optional engines for the Cyclone GT included the M-code 351 cubic inch 4-barrel with dual exhaust that was rated at 300 hp SAE gross (likely 260 hp SAE net) and was available with or without ram air induction, plus the other four 429 cubic inch engines.
While a convertible was offered for the Ford Torino in 1970 and 1971, no convertible was offered for the Mercury Montego and Mercury Cyclone in 1970 and 1971.
In 1971 the Mercury Cyclone became the Mercury Montego Cyclone. Once again the Cyclone had lost its individuality. The model line up was the Montego Cyclone, Montego Cyclone GT and Montego Cyclone Spoiler. It sold poorly; the production numbers for the Montego Cyclone for the '71 model year could be counted in triple figures. The Montego Cyclone GT did much better, but nothing like previous years. The following year there was no Cyclone nameplate. The Comet, where the Cyclone badge started, was reduced to a six cylinder as standard. Almost going full-circle back to the economy-car it was before '64.
The 351 cubic inch M-code was replaced by the 351 cubic inch Cobra Jet in May, 1971, for the Cyclone GT. (See Ford 335 engines.)