Makes › Ford › Mustang › First generation › Mustang 351 HO 'R-code' (1972) · Rare specification · 1972 Very Rare
Ford
Mustang 351 HO 'R-code' (1972)
Low-compression Boss 351-derived 351 HO; Marti lists 366 Mach 1s, 30 SportsRoofs, 14 hardtops, 13 convertibles, 5 Grandés
Still being researched: identification guide, full specifications. Everything shown is checked against the cited sources. Know more? Send us a source.
Contents
01Overview
At a glance
- Built
- 398 Built
- Years
- 1972
- Engine
- 5,750 cc / 5.8 LFactory: 351 cu in · converted
- Power
- 205 kW / 279 PSFactory: 275 hp · converted
- Top speed
- Not yet verified
- Body
- Not yet verified
- Designer
- Not yet verified
- In this archive
- Not yet verified
- Surviving
- Not yet verified
Sources and any conflicting figures are in the sections below.
Why it matters
The R-code 351 HO was the last high-output Mustang engine of the first generation, offered for a short time in 1972 after the Boss 351 and both 429s were dropped. It was a low-compression Boss 351, and the only 1972 engine option with a mandatory top-loader four-speed.
How rare is it?
Six separate kinds of rarity – never combined into one number.
Each kind of rarity is rated separately and never combined.
02Production & history
Production
Every figure says what it counts.
| What is counted | Figure | Basis | Status |
|---|---|---|---|
| Factory package production1972 Mustangs built with the R-code 351 HO engine | 3981,2 | Factory production | Factory reported |
Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.
History
For 1972 Ford offered a slightly detuned Boss 351 as the 351 HO, designated R code, which could be ordered on any model; only 398 Mustangs were built with it, all at Dearborn. The engine had a special high-lift cam, mechanical lifters, forged aluminium pistons and a special four-barrel manifold. Mandatory options were the top-loader four-speed, a competition N-case rear end and air-conditioning delete.
Variants
How each version differs from the standard Mustang 351 HO 'R-code' (1972).
No variants documented yet. Have a source? Contribute it.
03Specifications
Technical specifications
Engine
| Engine family | Not yet verified |
|---|---|
| Engine code | Not yet verified |
| Layout | Not yet verified |
| Displacement | 5,750 cc / 5.8 LFactory: 351 cu in · converted3 Independently researched |
| Bore | Not yet verified |
| Stroke | Not yet verified |
| Compression ratio | 9.0:13 Independently researched |
| Valvetrain | Mechanical lifters1 Independently researched |
| Fuel system | Four-barrel carburettor, first full-time cold air induction in a Mustang1 Independently researched |
| Power | 205 kW / 279 PSFactory: 275 hp · converted3 Independently researched |
| Power at | Not yet verified |
| Torque | Not yet verified |
Transmission & drivetrain
| Gearbox | 4-speed top loader manual (only transmission available)4 Independently researched |
|---|---|
| Gears | 44 Independently researched |
| Final drive | competition N-case rear end (mandatory)1 Independently researched |
| Driven wheels | Not yet verified |
Chassis, body & dimensions
| Chassis | Not yet verified |
|---|---|
| Front suspension | Not yet verified |
| Rear suspension | Not yet verified |
| Brakes | Not yet verified |
| Steering | Not yet verified |
| Body construction | Not yet verified |
| Wheelbase | Not yet verified |
| Length | Not yet verified |
| Width | Not yet verified |
| Height | Not yet verified |
| Front track | Not yet verified |
| Rear track | Not yet verified |
| Kerb weight | Not yet verified |
| Dry weight | Not yet verified |
Performance
| Maximum speed | Not yet verified |
|---|---|
| 0–100 km/h | Not yet verified |
| Fuel tank | Not yet verified |
“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.
04Colours & options
Factory colours & interiors
Original paint and trim, with the number of cars in each where a source gives it.
Not yet documented. Have a source? Contribute it.
Factory options & codes
Codes are shown exactly as written by the manufacturer.
Not yet documented. Have a source? Contribute it.
05Individual cars
Chassis register
Every documented car, with its colours, history and where it is now. Open a row for the full record. Known chassis are not automatically authenticated originals.
Not yet documented. Have a source? Contribute it.
Competition history
Every race result of the individual cars, in date order. Click a chassis number to open its full record in the register.
Not yet documented. Have a source? Contribute it.
Auction & sale history
Documented public sales of the individual cars. Click a chassis number to open its full record in the register.
Not yet documented. Have a source? Contribute it.
See one in person
Museums where an example of this car can be seen.
No example is documented on public display yet. Have a source? Contribute it.
06Reference
Identification guide
How to tell an original from a replica or later conversion.
Not yet documented. Have a source? Contribute it.
Sources
Each number links to the exact facts it supports.
-
1
1972 Ford Mustang: Ultimate In-Depth Guide Level A MustangSpecs
- Only 398 Mustangs were built with the drag race oriented R code motor
- mechanical lifters
- first full time cold air induction system in a Mustang
- competition N case rear end (427, 428, 429, Boss 351, 351HO)
-
2
Hagerty – 7 lesser-known Mustangs that are surprisingly uncommon Level C
- 366 1972 Mach 1s with the 351 HO (all body styles sum to 428)
-
3
1972 Ford Mustang fact sheet Level B Over-Drive Magazine
- The 351 CID HO (R-Code) 275 HP engine
- HO performance engine that ran 9.0:1
- 351 CID HO (R-Code) 275 HP
-
4
1972 Mustang General Information Level A 7173 Wiki
- the only transmission available was the 4 speed top loader
- 4 speed top loader
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