Opinions on '72 6 cyl vert

[secluff]

Hello MooseStang,
I know you already have the L code production numbers you asked about, so consider this list of all '72 body styles with the 250 6cyl a little extra fluff.

Trans code-------Coupe------Sportsroof------Vert---Total
(1) 3 sp manual--2,924-------271--------------209---3,404
(W) C-4 A/T------5,673-------341--------------356---6,370
.....................................................................Total '72 production 9,774

You can make the 250 perform slightly better, but without spending lots of big-time $$, you will not see a substantial increase in performance. Keep in mind that this engine family was engineered for the new '60 Falcon. The full-size Ford 223 six was too large for the new Falcon chassis, so this was designed from day one to be a small economy engine for the new compact car segment. It was a whopping 144 cubic inches! I had always heard it wouldn't pull a snail out of its shell. (There is another version of that I can't repeat here)! Even with the 170 and 200 engines, Shelby still called the '65-66 Mustangs a Secretary's car.
The 250 is a slightly larger version of this engine family but with very little part interchangeability.
Another problem is the intake manifold cast as part of the cylinder head. Not a problem when this engine was utilized as it was designed as an economy car engine. Performance enhancements that required more carburation required special resourceful "Engineering."
There was a shop tech who did help his son build a mini Shelby. They started with a '66 Mustang coupe with a 200 six. They used an Offenhauser adapter intake that used three 1bl carbs. The shop tech is a Ford-certified master tech, and the son had unlimited funds, and it took a lot of each other's talent (The techs' know-how and his son's $$$$) to get it running. It ran really well, but they could have bought a Motorsport 347 stroker engine for what they spent.
There is a site that specializes in making these straight six's run, but bring your $$$. They do offer the Offenhauser intake like used on the above-mentioned '66. There is also an aluminum head with a separate intake manifold for those so inclined. https://www.vintageinlines.com/
Since you already have a Q code 4sp for your speed, pleasure, and enjoyment, you may want to keep your six mostly stock when you see some hop-up parts prices and the ever-spirling price of gas!

@machattack, you can go to Marti's site and check out his books. The one I and many others use here is "Mustang...by the numbers (1967-1973)" https://www.martiauto.com/

 

[mrgmhale]

My first car, in 1971, was a 1969 Mustang HardTop (Coupe) with a 250 I6 , C4 auto tranny, P/S, and aftermarket "ARA" air conditioning. I never bothered looking at its rear axle ratio, but I am certain it was either 2.79:1 or 3.0:1, either of which is great for highway driving and fuel economy, but not so good for acceleration or spirited driving on town driving. That said, had I swapped in a 302, or even 351, the gears being as steep as they are would have worked against a more capable engine delivering the performance one might expect of a v-8. Not only do the suspension and brake systems "need" to be beefed up for a v-8, but in fairness to the larger engine one would need to get a lower ratio rear axle gear set, like 3.25:1 or 3.5:1, both of which provide a nice compromise for both in town driving and highway driving.

Our 73 Mustang vert has a 302 2v in it, with a 2.79:1 rear axle gear set. As nice it is to drive on the highway, around town it does not have the low end zip like our 73 Mach 1 has. The Mach 1 has a larger engine, but it also has 3.5:1 TractionLok gears in the rear axle housing which makes a lot of difference in how "snappy" the engine can perform around town.

Anyway, I am also of the opinion that it is better to keep a Mustang originally with a 6 cylinder as a 6 cylinder vehicle, as opposed to upgrading to a v-8. There is so much that has to be done to really let a v-8 perform in a well balanced vehicle. And, if you do end up making some performance changes to the 6 cylinder(or even v-8), be aware the rear axle gear ratio will have a tremendous impact on how the engine is able to perform. If you want spirited performance, look for a vehicle that has moderately steep ratio like 3.25:1 rear axle gears, or better yet 3.5:1, Anything lower than 3.5:1 (4.11:1 or lower) will perform even nicer, but you will also end up running closer to 3,500 or higher RPMs at 60 MPH - which is no fun for more than a few minutes.

If you can find a vehicle with Power Front Disc Brakes, get it. If you and up with a drum brake system, prepare yourself for an upgrade to a Front Power Disc Brake system, especially if you have a v-8 for an engine. I like Wildwood brake conversion kits. If you are moving from front drum to front disc brakes be sure to get a new Master Cylinder made for front disc brakes (no Residual Pressure Check Valve for the front calipers).

I happen to like 6 cylinder Mustangs, despite them not being able to "compete" with the v-8 Mustangs. They have a charm all their own.

 

[Lazarus]

I know a lot of the guys on here are pretty hard core originalists. I respect that. And I love straight sixes in lots of applications. Full size broncos with straight sixes are a really cool niche for example.

I say this with a serious debt of gratitude to the purists on this site who have taught me much: you gotta leave a little room for the classic American hot-rod spirit fellas! If we have to keep inline 6s original, then that’s pretty much it for any customization. Jeesh. I admire guys trying to preserve the legacy of classic American muscle... and mods are a part of that also. I don’t know, maybe I missed the cool character in the 60s and 70s movies that was wearing jeans with a crease in them arguing about correct serialized windshield wipers at the drive-in with the other greasers.

If I read the spirit of the post correctly, he has a car that is the more original one and wants one to play around with. I say go for it man! I am with you there. But I’d probably go ahead an plan on the v8 swap in the future, and not try too hard to supe up the 6.

I have had cars I couldn’t bring myself to modify... I had a 71 Blazer that was so pristine, I was unable to drill a few holes in it to install a rare half cab that I had already bought (and even drove 8 hours to get). I had a 65 survivor coupe with a 289 that was kept in such great shape by the previous owner (who had passed away) that I could not modify it. Then again, I had a 67 Camaro that was originally a straight six. I found myself liking it just a tad more with a 406 small block.

I say get the vert and make it your fun mod to sit next to your more fastidious classic. I bet you $5 I know which you’ll drive and enjoy more.

 

[MooseStang]

Any of you 6-cyl 3sp owners have a/c?