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Why can't I convert a 400i to a 5 speed??

Discussion in 'Technical Q&A' started by jm3, Jul 5, 2004.

  1. jm3

    jm3 F1 Rookie

    Oct 3, 2002
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    Someone must have done this.....
    Concievably, a blasphemous person could bolt in a 6 speed from a Camaro. The technology is definitely available in terms of drive shaft, shifter, u-joints etc.
    Any idea what the bellhousing pattern is similar to? (or the same as)

    Clutch pedal and linkage could be sourced new /used/fabricated.
    I mean, realistically, the change in value would be minimal, and the 400i seems to be much more plentiful than 365 or 400GT 2+2.

    Of course I would prefer a 365 GT 2+2 GT or an early 400 with carbs, prefer Silver, need all DOT releases, will pay fair price. PM me if you know of one for sale.
    Jay
     
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  3. mk e

    mk e F1 World Champ

    Oct 31, 2003
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    It seems like it should be pretty straight forward. You can just use the chevy bell housing with an adapter, then make up the length at the throwout bearing. Still a lot of work though, I'd plan at least 100 hours.
     
  4. thecarreaper

    thecarreaper F1 World Champ
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    Sep 30, 2003
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    it can be done, i actually looked into this a few months ago when i was making the decision on which car to get. the ferrari bolt pattern from the GM th400 trans would be easy to get a bellhousing made in, or get an adapter. the problem i had with looking into this was the flywheels for ferrari's are very expensive , and most of the dimensions i had would not work with any combination for any reasonable amount of money. making the exsisting ferrari / donor assembly work together would mean a new custom flywheel would have to be cut. most estimates from friends sources were in the $3k -$4k range for the flywheel, custom made to fit. the relationship to the clutch and the fact you would need some "service" replacement parts meant it was too much for me to want to handle. anyone know why a ferrari 5 speed from and earlier year v12 wont fit in a 400 series??? :)
     
  5. smg2

    smg2 F1 World Champ
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    not familiar with the bellhousing pattern on the ferrari's but i do know that lakewood makes bellhousings that are universal for most domestic makes that allow most any trany to be used. lakewood units are pricey though $300-500 andthats just the bellhousing. it would get you a tremec 5 or 6 speed if you could do it though. parts for trans and housing would be just shy of 4k.
    i'm gonna be using that set up for the cobra build behind a 466.
     
  6. smg2

    smg2 F1 World Champ
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    for the flywheel why not find a shop with a 3axis mill and have then mill out a billet unit and match it to the ferrari bolt pattern and crank then get yourself the replacement disk surface from summit and have them match it to that. that should get you a servicable and less expensive flywheel and replacement parts. the gear ring will be the tricky part though.
     
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  8. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
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    Maybe this is a stupid question, but why not just buy a 400 with a factory 5 speed? They made them with 5 speeds. I know many more were sold with autos but I saw one with a 5 speed on eBay a few months ago.

    Birdman
     
  9. GearHead

    GearHead Karting

    Jan 3, 2004
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    If you can find the 5 speed parts from a wrecked one, I'd imagine it would be a pretty easy swap, since the car was designed to be either a 5 speed or an automatic.

    I converted my 5 series BMW from an auto to a 5 speed. Bought the pedal box and shifter, transmission, driveshaft, flywheel, and other little bits and pieces from a wrecked car. Bought a new clutch, pressure plate, clutch and slave cylinder, and hydraulic lines new.

    Once I had all the parts in my garage, it took me less than a weekend to get the job done, working alone. Not too much different than replacing a clutch.
     
  10. mk e

    mk e F1 World Champ

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    Tilton quoted me $1000 when I was setting up the clutch I got from them. The gear is the only hard part, I guess I'd wire edm it. The other option is to simply set the new flywhell up so the ring gear section from your flex plate will bolt on.
     
  11. jm3

    jm3 F1 Rookie

    Oct 3, 2002
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    Part of my reason for posing this question is that I am frustrated trying to find one! Automatic 400's are all over the place, the only 5 speeds I have seen (2) and looked at were thrashed. Didn't see that one on ebay.

    Jay
     
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  13. Smiles

    Smiles Moderator
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    You can do it, but it won't be cost effective.

    The six-speed from Camaros and Corvettes is called the T-56.

    I don't believe that the TurboHydramatic transmission as used in the 400 has the same bolt pattern as other GM products. (If it does, a Muncie M-20 4-speed may be your easiest choice.) I think the TH400 has a similar bolt pattern to Jaguars or Rolls Royces.

    Start here for a Jaguar fellow's search for a gearbox:
    http://www.westnet.com/~mfrank/FiveSpeeds.htm

    Also do a search for a guy named Terry who does Jaguar conversions. He'll put a T-56 with a lightened flywheel into an E-type that will make it fly.

    One big thing to consider is where in the center console will the shifter poke out. It may be too close to the engine, or too close to the rear end. Some trannys (like the TKO T-5 5-speed) has three different shifter position options.

    I say: go ahead and do it! Do some research, find the right car and parts, and you'll be one proud man once the project is complete.

    --Matt
     
  14. judge4re

    judge4re F1 World Champ

    Apr 26, 2003
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    Don't do it. At the end of the day you'll have a bastard car that nobody wants. If you think automatics don't sell well, wait until you try and sell a modified one. The 400i's with the 5 speed box are out there. Patience and you'll find one.

    I've been looking for a 308 GTBi red/tan for over 6 months now, its part of the fun...
     
  15. slewman

    slewman Karting

    May 4, 2004
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    Buy a 400i 5sp. If you were to convert an auto to manual the easiest set-up would be from a wrecked 400i 5sp. The rear of the trans is supported by the torque tube and the torque tube supports the front of the differential. You would need flywheel with bolts, transmission with shifter, clutch, clutch fork, collar for release bearing, cable and linkage, pedal box, torque tube?, differential, and some small parts.
     
  16. dr.mike

    dr.mike Karting

    Oct 31, 2003
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    I actually considered this about 2 months ago. I had the engine out of my 400i and found out that the way they got the GM TH400 trans to fit was that they included a Ferrari to Chevy Adapter plate. You can literally bolt up a Chevrolet V8 bellhousing and a Doug Nash 5-speed transmission. You would have to make a small adapter for the crank bushing. And add in an aftermarket hydraulic clutch. I THINK all of the Ferrari flywheels are internally balanced. So an 330/365/400 flywheel would work. I would be tempted to make a custom flywheel that fitted a GM style disc/cover assembly.

    The Doug Nash 5 speed even uses the same driveshaft yoke pattern as the TH400. So, the driveshaft and yoke may be good to go, also. I may YET do this. My 400i is already bastardized by being converted to a cabrio anyway :) Maybe when I am done trashing the CIS and converting to EFI...
     

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