Btr 4 sp in early mustang

[Tony 65FB]

Hi all,

Looking to put a Windsor 5.0 and 4 sp BTR auto into a 65 mustang. I’m sure this has been posted before. I have read in the past the btr needs modification to fit in the tunnel? Also, can I use the box without the need to use the sensors?

If all too hard I will put a T5 behind it. Any advice welcome.

Thanks

Tony

[AussiePhil]

Hey Tony,
I’m not an expert on autos but I have a 5.0 EFI Windsor and a T5 in my 68.
As you know the Fox body and XR8 5.0 did come with a Borg Warner BTR attached to a EECIV ECU.
That combination would be great in a 66 Mustang but engine modifications are limited by the ECU.
If I was to go down that track again I would consider switching to a carburettor.
Cheers Phil.

[peter9231]

 I have a 5 litre EFI in mine with the BTR 4 speed,
Yes you need the sensors but no mods to the transmission or tunnel.
An XD falcon trans crossmember is what you need with an XF driveshaft.
All fits up and drives really well.
Peter

[Tony 65FB]

Thanks both of you.

For the sake of ease, I will be replacing the EFI with a standard intake and carb. Is it possible to use the btr without the sensors, like a Traditional auto?

What is easier to assemble? a BTR auto or a T5? I need simple as I will be doing the work myself. I know I need a modern drive line cross member for the T5.

Thanks

[peter9231]

No, BTR needs sensors and ECU to operate.
Stick with the EFI you wont believe how well it will drive.
Peter.

[AussiePhil]

I have a 5 litre EFI in mine with the BTR 4 speed,
Yes you need the sensors but no mods to the transmission or tunnel.
An XD falcon trans crossmember is what you need with an XF driveshaft.
All fits up and drives really well.
Peter

Hey Peter,
I agree the EFI is great, plenty of power, easy starting.
Nice job, like your tower bar, EFI creates a bit of a problem here, but looks like you snuck it under the bonnet nicely.
Cheers Phil.

[peter9231]

Thanks Phil,
Cleaned the install up a bit since then.
Its not as tight as it looks really.
The BTR is fantastic super smooth with the overdrive for cruising.
Done 20K since it went in and its been with faultless.
Fuel economy is unbelievable.
It sat for 7+ months last year (with a Ctek charger)  Reached in and turned the key and it started like it had just been turned off.
Peter.

[peter9231]

Thanks both of you.

For the sake of ease, I will be replacing the EFI with a standard intake and carb. Is it possible to use the btr without the sensors, like a Traditional auto?

What is easier to assemble? a BTR auto or a T5? I need simple as I will be doing the work myself. I know I need a modern drive line cross member for the T5.

Thanks

This may help answer some more questions.
Peter.

[Tony 65FB]

Thanks Peter.

Can I use the BTR and hook up sensors that don’t require an ECU for the engine? I.e, still replace EFI with carny? How difficult was it to wire in the ECU in an old Mustang - it’s the electrical that worries me.

I need to be able to do all this without spending vast amounts of money and can only have it off the road a short time as it is my daily.

Only doing this because my current engine/gearbox is dying.

Tony

[peter9231]

Tony,
You need to have a fair understanding of electrical systems to be able to attempt this.
It will not work without sensors and an ECU it would be difficult do do this with a carburettor conversion.
If you cant have it off the road for a reasonable amount of time then its probably not the conversion for you.
Removing the fuel injection and converting the engine to carburettor involves a fair bit of work in itself and kind of defeats the purpose.
You may be better off to recondition what you have.
Peter.

[pgold]

U S Shift who make controllers for AODE, 4R70W and GM auto have a TPS sensor to couple to HOLLEY carbs and looks to work in right voltage range for the BTR to learn.

[pgold]

Peter how much clearance is there between steering box and starter motor with BTR?

[peter9231]

Mine is LHD,
Starter is no where near the steering box.
The closest thing to the steering box is the exhaust manifold.
If you have the original power steering starter is close to the ram and needs a ram drop bracket.
I have a Borgeson steering box in mine.
The BTR needs a VSS - speed sensor - hard to fit with a speedo cable.
I fitted electronic speedo to mine.
Peter.

[Tony 65FB]

I’m sure there is plenty I haven’t thought of with this conversion to be sure Peter.

Full disclosure I’m getting rid of a tired 6 cylinder 3 speed. All the suspension and rear axle have been upgraded to v8, now just the running gear.

I’ve gone for the later model v8 because it’s newer and has the roller cam. Plus it’s ready to take unleaded. I would have thought the replacement of the EFI was a Windsor intake and carby? I’d be happy to keep the EFI but wonder how much work goes into wiring it all up?

Would it be a lot simpler to just put a 5 speed behind the new motor to avoid the electrical complexities or do the T5s have sensors also?

I’m definitely taking the opportunity to swap out the 6 for an 8 but also want the extra gear to
Lower the revs since I drive it so daily and will hopefully get better mileage. Anything would be better than the old 6 in it now.

[Tony 65FB]

I should add, mine is still LHD also.

I’ve thought about the BTR because it is so readily available and the T5 for a V8 is so much harder to find.

[Dwayne]

Another option is to go with an AOD box instead of the BTR. No electrics to deal with, just need a flex plate, crossmember and kick down cable from lokar.

[GEOFF289]

I’m sure there is plenty I haven’t thought of with this conversion to be sure Peter.

Full disclosure I’m getting rid of a tired 6 cylinder 3 speed. All the suspension and rear axle have been upgraded to v8, now just the running gear.

I’ve gone for the later model v8 because it’s newer and has the roller cam. Plus it’s ready to take unleaded. I would have thought the replacement of the EFI was a Windsor intake and carby? I’d be happy to keep the EFI but wonder how much work goes into wiring it all up?

Would it be a lot simpler to just put a 5 speed behind the new motor to avoid the electrical complexities or do the T5s have sensors also?

I’m definitely taking the opportunity to swap out the 6 for an 8 but also want the extra gear to
Lower the revs since I drive it so daily and will hopefully get better mileage. Anything would be better than the old 6 in it now.

For mine a 3 pedal car is much more fun but each to their own. A T5 into an early Mustang is pretty straightforward - as I often say, if I can do it anyone can. No electronics unless you want to run an electronic speedo but a normal cable Mustang speedo cable fits a T5 in place of the sensor they came with.

Losing the EFi and putting a carby on a roller cam 5.0 is also straightforward. You also need to put a distributor with the right gear in it, a mechanical fuel pump and, depending on what gear you want to run off the crank you might need to change the timing cover for the EFI one to an old style one.