Question about vintage 289 and modern tranny

I've got a '68 Mustang 289 that I'm wondering about mating up with a modern transmission (5 speeds or more).  Anyone do this?

In reply to grubeguy :

Is it going in the Mustang?  How built is the engine?  Daily driver or performance driving?

There are vendors that offer kits to install the common T5 trans out of the Fox Mustangs.  That trans is more then strong enough for any 289 short of a HiPo 289. If your worried you can always move up the the TKX 5 speed. 

In reply to grubeguy :

I've done it a time or two.  I'm actually collecting parts to do it in my early '65 Mustang now.  Feel free to reach out via site message anytime.  Ive been playing with Mustangs since they were still just used cars...

https://www.motortrend.com/how-to/mump-0307-how-to-install-a-five-speed-in-vintage-mustangs/

Quick review on what's involved. Definitely worth it and a solid replacement for a street driven early pony. I consider myself kind of a hack when it comes to conversions and I even found it to be pretty straight forward. 

jimbbski said:

There are vendors that offer kits to install the common T5 trans out of the Fox Mustangs.  That trans is more then strong enough for any 289 short of a HiPo 289. If your worried you can always move up the the TKX 5 speed. 

A Hi Po doesn't make significantly more torque than a regular 289, it mostly had stronger/better balanced internals, some of which became standard items like the extra thick main caps.

Plus, we're talking about 13ci here, it's not going to make or break anything that wasn't already going to work (or not work)

I should have been more specific - I'm looking for a modern automatic tranny.  The engine-tranny combo will go into an engineless classic Mercedes, weighing in at around 4000 lbs.  I don;t remember the rear end ratio on this thing, but remember being at 2500 rpm or more on the highway, at 55 mph. Thus, I want something more fuel efficient, something domestic, in case I have issues down the road, and something with a great knowledge base already baked in.

The engine is stock but has a knock, so it's going to get rebuilt (advice greatly accepted here as well). I'm looking for 300 hp or so, and an auto tranny to take the power and weight.

And when I say rebuilt, I'm going to have someone else do it for me. I'm great at welding and body work, but bad at engine rebuilds.

Anything will work.  As long as the engine is '66 or newer, there are a plethora of Ford transmissions to use, although I'd stick with one of the four speed models for simplicity.    I am fairly sure that the Mod motors' bolt pattern is the same, at least as used in trucks, so an electronic four speed with a simple controller would be easiest.

Auto transmissions with many gears tend to be "clutch to clutch" type, where they have to disengage solenoids as they engage others, and the timing is critical so the trans does not bind or run away as the shift is being completed, so there are very few if any stand alone transmission controllers available.

So how much HP can I get out that engine, without going back for a rebuild in 40k? Is 300hp reasonable?

K code 289 in Shelby's we're rated at 306hp though that was old timey HP rating.  Doable for sure.

Pete. (l33t FS) said:

I am fairly sure that the Mod motors' bolt pattern is the samed alone transmission controllers available.

Watch out for that one. The MOD pattern is only the same as the SBF pattern for the first few years. At that point Mods were only used in Panthers. 

Good to know about the bellhousing, I thought it was the other way around.  Or a Windsor/Romeo thing.

I personally would not want an AOD because you can fry them quickly if the TV cable setting is not right.  The Microsquirt trans controller can natively do the E4OD (IIRC this is basically a C6 with overdrive) and 4R70 (beefed AODE) and while it may seem a little more expensive initially, being electronically controlled means you don't have to spend money on shift kits or other things to get it to shift when and how you want.  A decent valve body costs about as much as the Microsquirt does, and won't be nearly as tunable.

All that said.  I had a customer with a K code clone '66 Mustang who brought it to me because ever since swapping out the manual trans for an AOD, the power brakes didn't work.  This made complete sense and the hard part was convincing the car's owner.  With the automatic, the engine was under load at stop lights, never had the throttle lifted off between gears, and it cruised at moderate load near idle speed most of the time because of the overdrive, instead of running at 1500ish in the city, 3000 on the highway.  In short, the engine was never building enough vacuum to charge the booster, and if it did it was used up in the first brake application.  I recommended a booster larger than the little 6" show booster, or a vacuum pump hidden in the fenderwell.  He took the car unsatisfied with this answer, even after I pointed out that the brakes worked great if you shifted to Neutral and revved/snapped the throttle shut a couple times.

Knowing now what I did not know then, I wonder if a brake boost helper would have worked without screwing the carb metering up too much.  Ford used this type on a lot of vehicles, Hyundai still uses it.  A lot of BMW and Volvo and other Euro cars use a device that looks different but does the same thing.

The hose with a clamp goes to the brake booster, the other large hose goes to manifold vacuum.  The device between the two has a venturi and small orifice, and the third hose goes to the air cleaner.  What happens is, even at WOT there is a pressure drop between the outside world and the intake manifold, this causes air to move through that hose, through the venturi.  Moving air is low pressure, so this creates vacuum for the brake booster, just like a carb makes a metering signal. 

So from a safe power output aspect, is a 351 a better choice for some mild tuning than a 289?  I'm looking for 300-350 hp, mated to an AOD. I'm reading in a number of places that the AOD can easily take 400hp without eating itself.

In reply to grubeguy :

The 351W is a much, much heavier duty block than any factory 8.2" deck block.  You need to spend a lot of money to get an aftermarket 8.2" deck block that is as strong as a common 351W.

Regarding the AOD... that's the first I have heard of that   They were eating themselves behind stock 225hp Mustangs when used hard.  Maybe they can easily take 400 marketing horsepower or Internet horsepower.  There is a lot of work that needs to be done inside to make them reliable behind 400 genuine horsepower.  You gotta figure that the T5 was the strong transmission option for a 5.0 Mustang.

The other thing to figure is that torque causes transmissions to slip, shock loads (mostly) cause them to break.  Note that Ford never, to my knowledge, put an AOD behind a 351W, they went straight for the E40D if it didn't just have a C6. 

I am trying to remember, but IIRC the biggest liability was the concentric input shafts.  This was so when in overdrive range, the transmission was powered directly from the torque converter shell instead of the turbine in the converter.  A crude but effective way to have a "lockup" converter.  One of the first things people had to do was rebuild the trans with a one piece input shaft and corresponding converter, which of course also gets rid of lockup, but if you wanted performance AND lockup then you'd start with a GM trans 

I love Fords but as a general rule, any Ford transmission with an overdrive is not very good.  C6s, Toploaders? Incredible.  C4s are even pretty good once given some tweaks.  

Well hmmm.  If I go the 351 route, I'm not looking to make a racer, just a reasonably well powered 70's sedan that might get raced at the stoplight now and then.  If I'm looking for a tranny stout enough for this, and with something in the 3 speed w/4th overdrive realm (or even more gearing), what's the best bet?

Rebuild in 40 thousand miles? You must be used to BMW or Porsche. LOL 

 I put 180,000+ miles on three different 302 based engines over the years. Two of them were stockish with mild bolt-on, 225-240 hp engines, the third had GT40 heads, Cobra intake, headers, mild cam, etc... it was probably a 270 - 280 horsepower engine. In a street car, a 300 hp "302" is pretty easy to accomplish, you can bore/stroke to 347 cubic inches in a stock block without too much effort. A 351 is going to provide more torque and is a stronger block.  The stronger block is really only a concern if you race the car. The 302 has a 50 oz balancer on the crank damper and the flywheel/ flex plate. A bad balancer plus, thin block casting, plus high RPM equals cracked block. On the street in a Mercedes cruiser, I don't think it will be an issue.  Having said that, a 351 with the proper build will be a torque monster. 
 

Edit to add, the first two cars had AODs and both needed rebuilds at 100ish thousand miles with a 20ish year old guy driving them. A more mature driver probably wouldn't destroy them too quickly if they are built properly. The TV cable to the throttle is important. It sets the shift pressure when you  accelerate. If it isn't set correctly, the pressure will be low and allow too much slippage. It burns up the clutch material in the transmission. 
 

The third car was a T5 World Class box. I replaced the clutch, resurfaced the flywheel, replaced the input bearing, replaced the throw out bearing, etc at 170,000 miles. I know you aren't interested in manual transmissions, but someone else may have an interest. 

In reply to Pete. (l33t FS) :

A stock AOD, nope. LMOL
 

There were modified AODs taking 300+ hp 20+ years ago. It was a pretty normal thing IIRC. 
 

Still a thing. AOD

I would look for a donor vehicle (80-92 V8 Ford vehicle), and pull the engine and trans together. That way the TV cable is set correctly from the start, of course you may need to revise it being it is a new car. For offered non electronic overdrive transmissions (pre 92) so That would be the simplest way to make sure you get all the parts you need for the swap, rather then piecing it together. You could contact someone like Gearstar and discuss your setup and they could recommend what you need (never used them, but I did look into them when exploring an AOD for a truck I am planning to build)

In regards to what Pete. said about vacuum, this is something to consider when choosing your cam (your intended power level). Or you could get an electronic vacuum pump (I have been told Volvos have them but never verified). Or you could go manual brakes (but at that weight I wouldn’t)

It is very easy to get 300+ hp from a 302. Starting in 85, the Windsors were roller cammed (and they offer retrofit kits for non roller blocks). There is a huge aftermarket for them obviously.. Mustangs… so it boils down to how much do you want to spend.. An affordable combo is a set of explorer GT40 “P” heads, a good cam and intake. Will get you close to 300.

To clarify what tester said, the 302 came with both a 28oz AND a 50oz balancer during its production run.. this is important when piecing it together so you get the properly balanced flex plate.

If you already have the 302 (or even a 289) I would look to stroking it to 331 before I sourced a 351W. I would recommend that rather then 347 because you have to do some serious clearancing on the block, and for a stock block it’s a roll of the dice. This advice came directly from my local machine shop.. If “I” were to build a 347, which is truthfully not a cruising type build, I would look into starting with a DART or BOSS 302 (new from FORD, not a vintage one) block ($$)