E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: superdave on January 08, 2018, 08:27:56 PM

Title: Three speed swap to four...
Post by: superdave on January 08, 2018, 08:27:56 PM
 :dunno: Pardon my ignorance but I wonder... we are working on a 318 car that will be a "Sunday driver". It had a three speed manual transmission and we plan to put a 4 speed in it. Does anyone know if we will need to change the rear end also? :thinking: As I recall that first gear was really "tall", I have seen a few 383s with a three speed and I could see myself smoking the clutch or tires or both getting things moving with that setup. :o  :rofl:
Title: Re: Three speed swap to four...
Post by: RUNCHARGER on January 08, 2018, 09:19:37 PM
It will depend on what your first gear ratio is in your 3 speed. I think they generally have a lower first gear than a regular 4 speed does so it might be a bit harder to get off the line than a 3 speed.  If your rear axle ratio is 3.23 that is generally what was standard with a 4 speed 340 or 383 car.
Title: Re: Three speed swap to four...
Post by: Chryco Psycho on January 11, 2018, 06:32:22 AM
the 3 speed is basically a wider ratio with only 3 speeds not 4 , no need to swap rear ends with the 4 speed
Title: Re: Three speed swap to four...
Post by: superdave on January 12, 2018, 07:22:04 PM
Quote from: Chryco Psycho on January 11, 2018, 06:32:22 AM
the 3 speed is basically a wider ratio with only 3 speeds not 4 , no need to swap rear ends with the 4 speed
Thank you. Now that I think about it that three speed seemed like they skipped first and you had to start in second or really close to it. :thumbdown:
Title: Re: Three speed swap to four...
Post by: Dakota on January 13, 2018, 05:17:17 AM
Just curious - is the drive shaft length the same for a stock 3 speed and 4 speed?
Title: Re: Three speed swap to four...
Post by: Chryco Psycho on January 14, 2018, 06:02:40 AM
I believe so