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Is 4 speed out of the question?


Guest zmaize

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Guest zmaize

I have a 4 speed manual tranny laying in my garage from a 66 (i think) chevelle. I'm already in the process of rebuilding the 327 from it, and i was wondering if the tranny would work, too. Can it be adapted to run a hydraulic clutch? I would like to try out this tranny first before i spend a fortune on something else (t56)

 

Has anyone used an old 4 speed in their conversion? Are the ratios too low?

 

Any input would be greatly appreciated.

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My friend Len (Fairlady 327) has a Muncie 4 speed in his 240Z. The ratios are perfect for drag racing, which is what he does best, but he totally needs a 5th gear because it spins too high on the freeway. It all depends on what kind of driving you'll do with the car. If you already have the tranny, great! They are very strong, but very short. Your shifter will be a tad bit forward of the "stock" location, even with the JTR setback position. Hopefully Lenster will chime in.

 

David

 

PS--he's feeling like the king of the street racing world since he beat that Skyline the other weekend. Hehe icon_smile.gif

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It can be used and a hydraulic clutch can be done a few ways, either with a slave cylinder from a camaro, etc., or with a hydraulic throw out bearing.

 

But the thing to consider is the issue of engine speed during cruise. If you plan on much highway use, the 1:1 top gear, coupled with the gears available for the diffs (3.36:1 being the lowest numerical available) and the short tires that fit in the Z mean that you'll be closer to 3000 rpm at 65 than 2000 rpm. Not a lot of fun for long on the highway with a V8.

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I've got the factory 4spd now w/my Inliner & its a PITB; I'm at mid 3500rpm's when I hit 70mph. In the mid summer-the floor boards get pretty hot from the exhaust; I can only imagine how much hotter a V8's exhaust will be.

 

If you got the $$'s then make the swap to a 5spd or 6spd now-you wont regret it. If money is short then put the 4spd in w/the expectation of going to an overdrive later. If money is short-then just get the car running & make the upgrades as the budget allows.

 

I'm one to talk-havent done my swap yet due to the lack of funds; I'm still holding out for a 6spd before I begin my swap. I've had projects in the past where I conceded & took short cuts....not this time/I want cruise to actually mean "CRUISE" when I'm in overdrive-that is why I'm holding out for a 6spd.

 

Like David said-it depends on the intention of the project; if the dragstrip is where the car will see the majority of driving-then go w/the 4spd; but, if you plan on Hwy driving at all...you will want an overdrive!

 

Kevin,

(Yea,Still an Inliner)

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  • 2 weeks later...
Guest Dean570z

My put would be to ask what type of driving are you planning on doing? My v8z with a 350/700r4 combo was real good for stop light launches and highway cruising. The trans is now very sick (another story) and I no longer have a 100 mile daily commute, so I am going with a Muncie 4 speed since I really miss the manual shift (price was right on the Muncie). I will be using the hydraulic throw-out bearing approach.

 

W. Dean Byers

Quartz Hill, Calif

570z since '93

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Guest Anonymous

Agreed, how your driving it will determine how suitable the 4 sp is. Theres nothing wrong with them, they're hella strong. Downside is top gear is going to be quite a few revs on the highway and top speed will definately be diminished. Another potential problem (depends on how you look at it really) is its shorter which either puts your linkage in the fuse box (or slightly behind it), or to the side of the tunnel unless you build a new mount with longer shift rod linkage.

They'll take alot of horsepower and torque though. For automatics, if I didn't run a overdrive automatic, I'd just use a powerglide. Parts are falling out of tree's in the aftermarket and in a light car they are the hot setup for drag racing. IMHO.

 

Regards,

 

Lone

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An important point implied in the previous post is that most Detroit 4-speeds tend to be externally shifted (the linkage rods are literally rods bolted to tabs on the outside of the transmission case), while 5 and 6 speeds tend to be internally shifted. This is one reason that the latter are physically longer.

 

My Doug Nash 5-speed (fifth gear is 1:1 - this is basically an Muncie "rock crusher" with an extra deep first gear) is externally shifted. Installation required radical modification of the transmission tunnel. I would guess that if you install an Muncie, a Saginaw, etc., you would have similar troubles. Now I'd like to switch to a T56, but I would have to undo many hours of custom sheet metal work.

 

But one advantage of the old 4-speeds is that they all bolt up to the aftermarket blow-proof bellhousings - an important point if you go racing. The T56, as far as I know, requires its own (non race-legal) bellhousing and clutch setup.

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  • 2 weeks later...

good points, hope im not too late too chime in here. i love my muncie to death, and if you have one ready, i say rockit, i run it with a 1"tilton mc to the stock datsun slave and a little adjustment to the pedal to make it engage and disengage right. yes the rpms are kinda high on the freeway, im at 2600-3000 but luckily i dont do too much freeway driving. i run the 3.36 and thats as good as it gets for now, i would like to swap to a wc t-5 or a doug nash five speed, because i could still use my scatter shield which may save my legs one day. one problem is the external linkage,it has binded up on me twice in the past, and i took a sawzall to my tranny tunnel and pulled it out and bolted up some new sheet metal that bulges for clearance, and hid it with carpet, not only does it work great for me, but when i need to pull the tranny i can almost do the whole job in the drivers seat! icon_smile.gif

what im trying to say is that once you have that setup going for you, you can have a lot more options for you that will rock the free world.

hope it helps

 

Leonard

"skyline killer, nissan killer"

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Guest Anonymous

i think lakewood makes a blowproof 6 speed bellhousing....dunno, might be wrong...if not, think i'm gonna invest in a tranny blanket...too many horror stories here at work, about clutch disks and the like trying to come through the floor board on really hard launches...

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