I use the Mustang Production Guide, Vol 2 for the info. It's apparently incorrect. I found a second source that indicates the 'Q' code was used in 71 to 73 for 351 4V engines but omits the 'R' code engine, and a third that shows 'Q' engines in 71 and 73, no 72, but has the 'R' code listed for 71 and 72. Your Marti report is a pretty good authority so to you, congratulations on your 351 4V 'Q' code. I'll stick to my 65 and 66 Fastbacks.
Jim

 

the q code is the engine. It was called the cobra jet while the stronger engine was Called High Output. If i remember correctly the difference between the two was in the intake but i cannot recall. so if you have a q code you have a 351 Clevland with a four barrel carb(4V) I'm actually restoring a 72' q-code mach one myself. also if you go to the autoparts store such as autozone they can look up your engine by code, which is really nice because of the two differnt put into the 72..are you doing a complete tear down?

 

Hello,
I am no expert, however Wikipedia was of great help.
ceswert

 

Not tearing the car down at all. It just needs a few things. Thanks for the info. Posted a pic in the "pics of your ride" thread.

 

"There were no Mustangs with the letter 'Q' in 71 and 72. "
Jim

Not sure where you got that information Jim. The Q code 351 Cobra Jet engine was available in both the 71 and 72 models.

 

Glen,
I know you're right, I can't find any viable back-up documentation that lists the code, the descriptive name, the displacementand the year together, and the non-Ford sources I do have are screwed up, the Mustang Production Guide, Vol 2, for one.
Jim

 

That's interesting. The red book doesn't show that there was a Q code in '71 but shows that there was one in '72 and '73.

 

One more time - well, one more.To quote 'The Official Mustang Price Guide' for 64 to 73 models, 2000-2001 edition (I don't buy these every year), there were 'Q' codes for years 69 to 73, 428 CID for 69 and 70, 351C CIDfor 71 to 73. The 71 listed at 280hp @ 5800 rpm, 345 ft lbs @ 3800 rpm, called a 'Cobra Jet' (Ram Air was code 'M', Boss 351 was code 'R'). The 72 and 73 listed at 266hp @ 5400 rpm, 301 ft lbs @ 3600 rpm. The 73 was called a 'Cobra Jet, the 72 was not listed with any special name. Note the drop in horse power in the 71 to 73 years.
Jim

 

1971-72 you could opt for a Q code 351C-4v low compression Cobra Jet that only had about 280 horsepower. The 73's were even lower compression.
http://reviews.ebay.com/Ford-351-Cle...AT:-1:STORES:3

 

I have a 1972 mustang covertible that is a q code is that rare informatiom I've been reading my car is one out of 13 that has that motor