3sp on the floor to 4sp

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scamp80602

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I'm looking at a 73 318 Duster with a 3sp on the floor - all original, never been modified. How hard would it be to put in a 4sp in it?? Thanks in advance!
 
You'll need to cut a hole in the floor pan to allow the 4 speed shifter & linkage to fit. Then cover it with a 4 speed hump from a donor car, maybe somebody makes a repop of it, or fab your own cover. I think your bellhousing will have the bolt pattern for the 4 speed trans, but not 100% positive. Pretty sure the clutch linkage & clutch assy will work.
 
He already has a floor hump if it's a manual 3 speed on the floor.

It's an easy swap as long as the bell is drilled for a 4 speed pattern. Trans, shifter, and maybe a different yoke.
 
It's been so long since I've seen a 3 speed on the floor that I wasn't sure if they had a hump or not. I know my Mom's 65 Barracuda didn't have one, but it was column shift. I'm sure crackedback knows more about it than I do.
 
I've the same question, but for a 70 Cuda (same 318, and 3spd). Wouldn't both manuals be interchangeable without modifing?
 
I am going to do the same swap myself on a 1974 Duster. I have not done it yet nor have I done this swap in the past. But, what I have been told is the biggest items you will need is the 4-Speed Tranny, 4-Speed Mounting Plate, 4-Speed Linkage, and 4-Speed Shifter Handle.

Also, I believe the yoke on the driveshaft may need to be changed to accomodate the 4-Speed.

I hope this helps. Hopefully, somone who has done this swap before will chime in.

Thanks,
 
scuba0331 said:
I am going to do the same swap myself on a 1974 Duster. I have not done it yet nor have I done this swap in the past. But, what I have been told is the biggest items you will need is the 4-Speed Tranny, 4-Speed Mounting Plate, 4-Speed Linkage, and 4-Speed Shifter Handle.

Also, I believe the yoke on the driveshaft may need to be changed to accomodate the 4-Speed. Thanks,
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Where would one find this? Is there an aftermarket supplier? I am thinking that original equipment may be hard to come by, plus expensive, and not always in good shape. I do have a 4sp tranny, but no 4spd linkage, or mounting plate.

Sorry, not trying to hijack the thread, just have the same questions, but mine are for a 70 cuda.
 
cbrxxtreme said:
Sorry, not trying to hijack the thread, just have the same questions, but mine are for a 70 cuda.
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I changed my 72 Challenger from factory 3 speed on floor to 4 speed.

Make sure the trans is for a E body ( I think E & B used same one, long tail stock)

once you get the trans should bolt right in.

Just make sure the input spline is the same and overall lenght the same. The 4 speed I got was out of a 440 6 PAK Cuda and I got everything since they changed it over to auto. Used the same drive shaft, but had to get 18 spline clutch since it was a Hemi 4 speed ( needed clutch anyway)
 
I went from a 3spd column shifted manual to a floor shifted 4spd in my Barracuda.

The 3 spd bell housing only had the 3pd bolt pattern so I needed to pick up an other bell housing. Both the \6 4spd bell housing and the v8 bell housing I am now using have bolt patterns for both 3spd and 4 spd. If you crawl unde your car and look at the surface where the tranny bolts on and see another set of bolt holes outside the 3spd pattern you should be set to go.

There are two body style 4spds, the short tail shaft for A/F bodies and the long tail shaft for B/C/E bodies, the long tails shaft unit also came in pick-ups and vans. The long tail shaft can be used in A-bodies with very little extra work. I have the long tails shaft in my A-body Cuda, I needed to fabricate a bracket that mounted to the rear tranny shifter pad and positioned the shifter forward to the A-body position and have the drive shaft shortened approx. 3 1/8".

Most all the 4spds have a bigger output shaft (have heard of but never seen one with the smaller output shaft) so you will likely need a new slip yoke. The other thing to watch for is the hemi and 440 car 4spds have a bigger 18 spline input shaft, it you happened to luck into one of those you will need a minimum a new clutch disk with the 18 splines and a new through out bearing that accommodates the larger bearing support sleeve.

If you need a shifter the Hurst Indy shifter is a steal. For $150 from Jegs or Summit you get the shifter, rods, levers for the tranny, mount and all the harware and clips. Only down side is the handle is short but it is a bolt on so a different handle is as close as the nearest swap meet or you could likely adapt the handle from your 3 spd.
 
CBRXXTREME

I got all of my parts from Passon Performance even the tranny. I haven't installed it yet but I heard nothing but great things about Jamie Passon's work.

Also, I believe you could all of these things from Brewers.

Good Luck.
 
scamp80602 said:
I'm looking at a 73 318 Duster with a 3sp on the floor - all original, never been modified. How hard would it be to put in a 4sp in it?? Thanks in advance!
Click to expand...

For the original question...if its 3 spd auto..you got lots of work. if its 3 spd manual, it will be pretty easy, just need everything for a 4 spd is all.

Phil
 
scuba0331 said:
CBRXXTREME

I got all of my parts from Passon Performance even the tranny. I haven't installed it yet but I heard nothing but great things about Jamie Passon's work.

Also, I believe you could all of these things from Brewers.

Good Luck.
Click to expand...

Cool, thanks for the input, me and pops have been talking about it for a while, and he has a 4sp (no idea which one). Summers are short, and winters are long in upstate NY, so we are gonna drive the car, and enjoy it this summer. Maybe if I have my garage back we'll work on it over the winter.
 
I have ourchased from Brewers performanc, I highly recomend them too, They will answer anything.

Phil
 
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