1965 Mustang Fastback
Engine Swap Options

by Prem Gill

Classic Mustang 289 V8 Engine Swap

Classic Mustang 289 V8 Engine Swap


Hi, what a great site you have.

I am fairly new to Mustangs, but my dream car from childhood was always a 1965 Mustang Fastback, So the time has come for me to find and complete a Mustang restoration project.

I was wondering what engines, new or old, can be fitted to a 1965 Mustang Fastback and where can these engines be purchased ?

Many Thanks


Hi Prem !

Thanks for your comments! The 1965 Mustang fastback has to be THE iconic Ford Mustang. There are many possible 1965 Mustang Fastback Engine Swap options.

If you've had a chance to check out the 1965 Ford Mustang section, you'll know that the V8 options were a base 260 cubic inch V8 for the early 1964 1/2 models and a 289 cubic inch v8 for later 1965 cars.

While a big block 390 V8 became available in 1967, (I know I'm going to hear about this..) most people who I know that did the swap, didn't find it to be great for these early cars, due to the excess front end weight and heavy stress on the front end and brakes.

They don't handle well either.

Ford Engine Candidates

There are a number of engines that will fit the 1965 Mustang fastback, with varying degrees of ease.

The easiest swaps would be to install either a 289,302 or 351 V8.

Small block Windsor and Cleveland V8 engines use the same engine mounts,so that's an easy one. And transmission and linkage choices are simple as well.

The 351W (Windsor) is a common swap for a number of reasons, assuming you don't want to limit yourself to original engines. The 351 is a big, strong engine, capable of producing a lot of horsepower and torque and taking abuse.

Speed parts are plentiful and several companies, like Hooker make bolt-in engine swap headers for the 1965 Mustang fastback, that fit so that you don't have any cutting to do.

If your car has the original Mustang 4 speed transmission, you can either opt for a later 1969-70 Z-bar clutch linkage, or convert to a cable operated system.

And if you're running a higher profile intake manifold, you can opt for
the convertible style engine mounts, which drop the engine down about 1/2 inch.

Newer Engines

A 1980's to 1990's 5.0 Liter Mustang engine and AOD transmission is also a popular 1965 Mustang Fastback Engine Swap. Not only are there a huge variety of go fast parts available, but you gain the added reliability of the EFI engine, along with an overdrive gear that will dramatically improve gas mileage.

The AOD, is about an inch longer than the Mustang C4 transmission, so either the driveshaft will have to be shortened, or a custom made piece will have to be found.

The other issue, is that the newer 5.0 Mustang engine has a serpentine belt arrangement, which powers a reverse rotation water pump and outlet, that necessitates having a radiator which has a lower radiator outlet on the driver's side of the engine bay.

The dip stick also needs to be relocated into a front timing cover location and the original hole plugged.

Most people stick with the serpentine arrangement, rather than convert to an old style V-belt setup, as you'd also need to convert pulleys and install a new forward rotation water pump.

If you plan to use the old style z-bar for a standard transmission, you'll also need an adapter kit to locate the threaded z-bar pivot onto the side of the engine.

Locating a Donor Engine

Since you're in the UK, finding engines for your 1965 Mustang Fastback Engine Swap can be more challenging.

Starting with used engines, you could certainly check out EBAy, but I'd start locally first.

There are many Ford Mustang enthusiasts in the UK and quite a number of early pony cars.

I'd recommend that you seek out the UK Ford Mustang car clubs as well as other Ford Car clubs. You may not have to go far to find just what you need.

If you want to go for a new crate engine, you have many choices, like Summit, Ford Racing and others that can supply you with a complete built small block engine that will turn your 1965 Mustang Fastback into a rocket!

Good Luck! Send us some pictures when you start your restoration project.


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Comments for 1965 Mustang Fastback
Engine Swap Options

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Engine swaps
by: J Comerford

First, I own a 1964.5 Mustang C code, 289 4V, A/T, P/S, P/B, and yes fuel mileage (89 oct) is not good.

12 mpg city/highway ?.

However, I am a purist and believe changing engine/transmission only ruins the value and spirit of the original US pony (sports) car. In other words it is what it is, a rough sports car by todays standard, but that is the beauty and 'soul' of it.

If you must swap then the 302 is the best choice without forcing the mediocre suspension and braking systems beyond their capabilities. Larger engines necessitate changing these systems too and you have destroyed what the car was designed to be.

Engine fittings?
by: Anonymous

Hi, I'm thinking of buying a 1974 mustang II that has no engine or trans. I have found an engine and trans from a 1990 mustang (2.3 liter).

Will it fit? I hope it would fit perfectly since it's the same engine size that came in it, but the two decades apart is what worries me. What will need to be done to fit this engine and transmission in the car?

Re Engine Fittings:

Your should be good to with the engine. That engine in various configurations was used in the Pinto, Mustang, Mustang 11 (derived from the Pinto) and others.

Where you can have a slight issue is going to be in the transmission. Your 70's vintage transmissions (automatic, not standard transmissions)have gone from fully mechanical, to varying degrees of electronically operated.

The 1990 Ford Mustang transmissions have an electric overdrive feature which will need to be taken into consideration.

Consult a 90's repair manual for the electrical details and wiring diagram. The good news with the change to an AOD is that fuel economy should improve and depending on the transmission gear ratios compared to those from the original Mustang 11, you may see better acceleration as well.

As far as the transmission mounts go, you will have to check it in place to see what does or does not line up.

My understanding is that the AOD is going to sit back about 2.5 inches farther than the original 3 speed automatic, so you will likely have to do some minor fabrication of the mount brackets.

Also the bell of the transmission is a bit larger and it may take a little "massaging with a hammer to get enough clearance in the top of the transmission tunnel to prevent rubbing or vibrations.

This transmission needs a cable attachment to the shifter and some mods of the linkage arm is likely to get the gear settings to line up in the shifter housing.

If you have the fabrication abilities, then it can be a nice swap. If not, or you don't have the budget to have someone else do it for you, it might be an idea to mate the engine to an older non AOD transmission or find a vintage original one.

Hope that helps.

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