First off, I’ve seen this car as well. The 1971 Big Block cars are a select group of what we would call the ‘Holy Grail’ of classic Mustangs. In fact, 1971 was a watershed year for the rarest performance Mustangs with the standard 429’s together with the CJ and SCJ options and the Boss 351 reputed to be the fastest of all the classic Mustangs. The Mustang in 1971 went out on a high at the end of the muscle car era. And Imo, these 1971 to 1973 Mustangs are the most stunning of all, horn cars didn’t get any hornier than these years, especially if optioned right.
I feel somewhat qualified to give you advice as I have owned several classics including a ’65 vert, ’69 Mach 1 and a ’73 Mach1. Did a lot of research on the ‘Long Nose Mustangs’ and found them to be better engineered than the earlier cars as the bodies are more solid which supports sturdier suspension mountings thus helping them handle and ride better than the earlier cars as well. A bit more modern too as you would expect after six years of development.
This write up is taken from the ‘Mustang Specs’ website –
‘With the 427 and 428 engines history by 1971, the replacement 429 CJ engine was called for duty as the top Mustang engine. The 429 belonged to the Ford 385 Engine Series and as such, no parts were interchangeable with the older 428. Wider, larger, and heavier, the 429 would not readily fit into the 1970 Mustang engine compartment, which is one of the reasons why the 1971 Mustang got bigger. The cylinder block was a variation of the 429/460 block, of which the Boss 429 was also based on; the cylinder heads were similar to the 351 Cleveland in design. You could describe the 429 as a large Boss 302.
As equipped in the Mustang, the 429CJ came with four-bolt mains, forged rods and pistons, 11.3:1 compression ratio, a hydraulic cam, (similar to the Boss 429’s) very large ports and valves, and all 429CJs came with aluminium valve covers. The 429CJ came with a Rochester Quadrajet four-barrel carburettor, and some early units had adjustable valve trains.
The 429CJ became a 429SCJ if the Drag Pack option was ordered. It consisted of a 3.91 or 4.30 rear axle ratio with Traction Lock or a 4.11 ratio with a Detroit Locker rear. It used a new thin wall casting block to keep the weight down, high-flow BOSS 302 style canted valves, and it could be bored out to over 500 cubic inches to keep professional racers happy. Some Mustangs with the Drag Pack also included an external engine oil cooler, though of a different design than previously used. The SCJ engine came with a Holley 780 cfm carburettor rather than the Rochester Quadrajet, a mechanical lifter camshaft and adjustable rocker arms'.
Production numbers make this a rare model -
J-code 429-4V CJ Ram Air V-8: 958 total
- 251 4-speeds: 7 hardtops, 1 Grandé, 9 SportsRoofs, 230 Mach 1's, 4 convertibles. With only 230 Mach 1 specced like this, how many are left is a question, but this makes this car even more valuable and collectible guaranteed.
In terms of value, perfect cars, read concours are around US$100,000 (see link). Convert that to Australian dollars with the exchange rate around 70 cents compared to the US dollar and you’re looking at a mint ’71 429CJ around mid $140k odd. Import one and the price landed in Australia may be around $160k. ’71 429SC Jet’s would be even more citing the above condition caveats.
https://www.topcarrating.com/1971-ford-mustang-mach-1-429-cobra-jet.phpSo there you have it. It seems this is a genuine ’71 429CJ car that’s priced reasonably. Appears there are minor details that need attention but nothing that would dissuade me from looking further into this car. The numbers matching aspect look ok but the drivetrain single digit anomalies would need further investigation. Again, if it were me, I’d talk to a Mustang Owner’s Club of Australia Western Australia representative to look at it and ask questions although experts in the ’71 to ’73 cars are not as prevalent as people knowing the early cars. The Victorian club president owns a ’72 and I have built up a fair degree of knowledge as I did a hell of a lot of research on these cars prior to purchasing my ’73 although we’re in Melbourne but would assist if I were in WA. Funnily enough, I was only looking for Bright Red or Pewter Metallic cars myself as these colors really compliment that sleek design, moreso the fastbacks and verts. Settled on a Bright Red ’73 Mach 1 also.
Hope that helps and good luck with the car if you wish to go further, I would suggest more research is needed as this may be a car that really is worth the trouble. Certain these ‘Holy Grail Mustangs’ will be good investment material too if that’s your motivation as well.