OK I'll break it down by year. & add sales. 1970, no doubt Mustang wins on performance & braking, since the basic chassis shares most components, given equal tires I'd say handling same. 1971-1973 More or less same as above. 1974 Mustang lost it's V8, other items equal. 1975-1977 Mustang & Maverick both have same asthmatic 302 & similar brakes. Mustang would probably out handle Maverick though not by much. Maverick was introduced at end of performance era, sales of Hi-Po models was in the dumper. As I've said probably a dozen times prior, building cars is all about sales. If they'd have sold, Ford would have built Honey Wagons. For fun I've included year for year sales. Comparison of first year sales of each, Mustang slaughtered Maverick. One has to remember there'd been nothing to comparable to Mustang, probably 75% of the buying public was excited. On other hand, Maverick was fresh but had no major styling innovations, jumped in pool with Camaro, Challenger etc. The '70 Maverick sold 451,081 units(doesn't include 127,833 '69½), '70 Stang 190,727 1971, Mav 271,897(Comet nabbed 83,000), New Mustang 149,678(oops, can't win 'em all). 1972, Mav 254,954, Stang 125,903(lowest to date) 1973, Mav 291,675, Stang 134,867(run to buy last convertibles propped up sales) (Last models before gas crunch.) 1974, Mav jumped to 301,048 with Comet nabbing 125,695(total 426,743), first year for ugly snow plow bumpers on both ends. New '74 Stang(without V8) 385,933. Sales for both slid in '75(enter Granada), Mav only 162,572, Stang 188,575(302 V8 now avail). 1976, sales fell again Mav 139,687, Mustang 187,567 1977, last year for old hat Maverick 98,506, Stang 153,173(both models basically same as '76) 1978, last year Stang II 192,410. 1979, first year Fox Stang 369,936. The new Capri 110,144 sales. Lumped together 480,080 or #3 on all time Mustang sales list. Beat out '67 472,121. Notice a trait here? New models almost always out sell previous. Obviously 1971-'73 Mustang missed it's target, total sales for three years combined 410,448.
The last Mustang of the 1970s was the 1973 model. The "Mustang II" is not a Mustang. It's a Pinto. If you're looking at it only in terms of sales, a lower cost car will always sell more units than a more expensive car. 1972 was the last year for "performance" (and it was way down). If a person looking to buy a ponycar in 1971 could get a lighter-weight and slightly less expensive (due to fewer luxury items) car like the Maverick with the same engine options as a Mustang Mach 1, they would be more likely to buy the Maverick instead of the Mustang. A 351w 4-V would easily fit had the spring towers not been made so wide (wider than the '60s Mustangs). Even the standard 302 with a 4-barrel, a little more cam, a little more gear, and dual exhausts would have made the car a performer for its time. Who was gonna buy a '71-'73 Mustang if the Maverick would have smoked it in the quarter mile? People looking for an economy car could buy the Pinto. Obviously a BOSS 302 in the '70 model would have defeated the original purpose of the car, and would be gone the following year anyway. Yeah, it would be great to re-write history, but the reality is that we have to make these cars into what we want, or what we think they should have been from the beginning...
You'll never convince me sales, proffitt and contentment of stockholders wasn't the driving force. Take something simple, 4-speed transmission, easy enough. Unlike 4bbl 302(discontinued for '69), Ford was still cranking those out. In '71 let's say Maverick sold another 7,500 units(no doubt smaller figures in subsequent years). Was that worth the logistics of additional parts mfgring, transmission assembly line workers, part stockage, etc, etc? Would painting a performance image scare off the core buyers? Boss 302, cool but that'd require recertifying, crash testing, modifying chassis for dual exhaust, fitting a 9" rear and again etc, etc. Before repeating there was no Boss 302 in '71, at least two were built, one survives. That one was a introductory show unit and was sent to dealer. In a 11:59 hour decision, cancelled. That Boss 302 then sent to 2nd dealer who swapped out engine for a 2bbl 351. Ford authorized VIN change from G code to R & then to H. Car showed up on ebay a few years back and buyer recognized it as the Boss 302 show car.
No reason to argue this point any further as it has been argued many times before with no end result. A reasoning for Ford's decision in the making of the Maverick/Comet line and associated options can never be proven, at least not at this late date. You both make very good points and are very knowledgeable on the subject, but something that cannot be proven one way or another is just food for thought and fun to play what if or what could have been. Most of us would have liked to have had Ford manufacture a hot Maverick that would have kicked some Mustang butt in performance, but it wasn't to be. Therefore, Ford left it up to us now and others at the time to make those performance Mavericks and Comets. There were many race Mavericks and Comets out there in the 70s. Maybe that is why people today at a car show will walk right by a Mustang with a ram air 428 to look at and ask questions about your hopped up 302 Maverick or Comet! Just saying.
Rick's correct, still I find it fun tossing the stones back. I compiled those numbers in response to a poster over on Torino board saying & I quote... "Ford uglyfied the Maverick so it would not out sell Mustang". When I asked where he got that idea, "everything I've read it on the net says that". So I turned loose with the numbers. OK, let's swing from a different branch of the Ford family tree, Torino/Fairlane. Till the Boss engines, drive line options were exactly same. None of the "you can't have this or that"(there's a small fib or two in there). Models like my Cobra came std with 428CJ & 4-speed. Didn't want the biggest motor? Buy something else. Even in those cars, sales slipped every year they were produced. The '70 models sales were just half of '69 & in '71, barely over 3000. Performance wasn't selling. For '70 Mustang Mach 1 soldiered on with the 428 as top dog(351 2bbl std), while Torino got the new 429CJ & SCJ engines. Mostly 428CJ grabs the spotlight, but a 429SCJ with 11.3 compression & solid lifter cam was BAD ASS. Mustang did get the option in '71. Mustang got the Boss 302 as they were heavily into Trans Am racing, Pony cars, 5 Litre limit. The Boss 429 was to be released in Torino(NASCAR) but when Bunkie Knudsen became president of Ford, he dictated change to Mustang. Reasoning, the race engine would be easier to sell in Mustang.