3 to 4 Speed Conversion

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‘72 Demon

‘72 Demon

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What parts would be needed to convert a 3 speed manual floor shift to a 4 speed? It’s for a 72 Demon with 318. Thanks.
 
A transmission, shifter and linkage, correct length drive shaft, maybe a different bell housing. I say maybe as your's may be dual pattern for both 3 and 4 spd transmissions. You'll need to get under the car and look.
 
Piece of cake and your teener is gonna love the short splits.
If you get an opportunity to obtain an early-A box with the 3.09 low gear, your teener is gonna love that even more. However the early-A comes with a Ball and Trunion drive flange that has to be converted at additional expense,namely a different mainshaft and extension.
EDIT; between the A230 and the A833,from 67 up,I'm pretty sure the driveshaft length is the same.
Not sure about the slip-yokes.
My early-A, with the large diameter mainshaft installed, seems to be every bit as strong as the 2.66low box.
I haven't been able to blow it up...yet.
 
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AJ/FormS said:
Piece of cake and your teener is gonna love the short splits.
If you get an opportunity to obtain an early-A box with the 3.09 low gear, your teener is gonna love that even more. However the early-A comes with a Ball and Trunion drive flange that has to be converted at additional expense,namely a different mainshaft and extension.
I'm pretty sure the driveshaft length is the same. Not sure about the slip-yokes.
Mine seems to be every bit as strong as the 2.66low box;I installed the large diameter mainshaft.
I haven't been able to blow it up...yet.
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The car is a 72, not need to worry about B & T drive shaft
 
AJ/FormS said:
If you get an opportunity to obtain an early-A box with the 3.09 low gear, your teener is gonna love that even more. However the early-A comes with a Ball and Trunion drive flange that has to be converted at additional expense,namely a different mainshaft and extension.
Click to expand...

Or use the conversion driveshaft as outlined at the early Barracuda website. That’s what i’m Using with my 65 ball and trunnions 833.
 
AJ/FormS said:
Was it any more economical than converting the trans? Jus asking
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IDK as another member put it up for sale at a great price and I grabbed it knowing I would need it.

To be honest, it’s the first I’ve heard about converting the mainshaft and extension. I would guess unless one already had the parts, people are reluctant to part out a transmission and would rather sell it whole. With that conversion do you lose the rear bearing which dies make the B & T 833 a pretty stout piece.
 
Hyup rear bearing is gone.
I ordered the used gearset from Passon Performance, along with one of his aluminum boxes, a re-inforced side cover, and a B/E body length mainshaft, to be used with a GVOD; which requires the long shaft. The rest of the parts I had as spares.
The shifter had to be moved back, well, actually I always hated it being so far forward,so I moved it back cuz this was the ideal time. It is now between the buckets and I love it there.
 
‘72 Demon said:
Thanks for the info. Doesn’t sound like too much trouble to convert.
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I’ve got a complete early 3.09 4 speed a with later 340 bell and flywheel/clutch. Pm me if interested. Not rusted garbage like similar lunatics selling things on this site.

Jake
 
I have a 3.09 first gear 4 speed, and I tell you what, I love that first gear 3.09. lol Excellent pull ya out of the hole gear.
 
mopardude318 said:
I have a 3.09 first gear 4 speed, and I tell you what, I love that first gear 3.09. lol Excellent pull ya out of the hole gear.
Click to expand...
Works real good with 3.55s, and not too bad with 3.23s if you got a bit of a torquey engine. But if you have an 8/1 teener with a 268* cam ;well.......... it's probably better to have an automatic and a big TC.
 
I figure with my 10.5 to 1 273/235, the 4 speed and 3.23’s in my wagon, it ought to run OK
 
Ummm you saying my starter gear should be 9.98 and if I went to 355’d then it would be 10.97?
 
Yes; that would be 10% more TM making your engine feel 10% bigger on the start line. and thru every gear. The one and only downside is that it also increases your cruise rpm by that same 10%
My 367 is a powerhouse at low rpm. It's a dump the clutch and go deal. That's TM in action.
With the 2.66 low and 3.23s, she was kindof a dog on the start line, with the starter gear being just 8.59. My new starter of 10.97 increases the TM by nearly 28% . That is flippin huge improvement, easily compensating for the cam-change from a 223* to a 230*.
A 10.97 starter gear is equivalent to 10.97/2.66=4.12 with a regular 4-speed. But second is still the same 1.92. So your engine needs torque at the bottom of second gear, or else you have to carry first gear a few hundred rpm further. I like to granny-shift 1-2 at no more than 2800, cuz the pipes are singing sweetly.
I like 3.55s because top of second is 5100 rpm at 60mph, right on,or close to the power peak, of my 223* cam, making my zero to 60 about as quick as it can be...... whereas 3.23s is 10% less or about 4600.For street performance, it's really hard to better 3.55s, with a manual trans, and a 5000 rpm power peak,which is about a 268* advertised cam.
A 9.98 starter is still fabulous in an Early-A, cuz of the weight difference. You are easily 10% lighter than my 68 Barracuda tank. That's why I had to go with a 360; at 3650# (me in it) anything less would have been to slow-performance for me. 10 pounds per cubic inch is always a winner.
My comment was just supposed to be funny.Sorry, that it wasn't.
 
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