23 spline vs. 18 spline manual transmission

[440charger68]

Will a 23 Spline manual 4 speed work on a 440 magnum? or do i need a 18 spline? I heard that 23 spline only works on 383. I need info because i have a deal waiting for me.

[Charger-Bodie]

a 23 spline will work fine unless you are gonna build the gine up alot

[Troy]

Cars with 383s or small blocks *came with* a 23 spline transmission from the factory whereas a 440 or Hemi would have had the stronger 18 spline. As for "will it work" - that depends on how much power you want to lay down and how hard you're going to beat on it. You'd obviously need a big block bell housing which will fit any big block. The iron ones with a 626 or 262 for the last three digits on the part number are for the 143 tooth flywheel and 11" clutch. There is a smaller one for 1970 and later for use with the 10.5" clutch and 130 tooth flywheel. As long as these parts all match you can use either setup. There are two different tail shaft housings (a second trans mount location was added for 1970 and later) but, provided you're putting this in a 68 Charger, you don't need to worry about it so you can use just about any one that you find. There is also a later 4-speed overdrive which also has 23 splines. These usually have an aluminum case and are probably not a great idea for a race/built 440 but they have been known to hold up perfectly fine for a touring/street car and you get the benefit of OD. There's also a later OD trans for trucks that has a granny first gear - NOT what you want!

Here are some great links that I use all the time:
http://www.autohobbydigest.com/a-4spd.html
http://www.slantsix.org/articles/4-speeds/ODA833fourspeed1.htm
http://www.bigblockdart.com/techpages/4sptech.shtml

Troy

[Chatt69chgr]

I believe the 23 spline units are good up to 600 #-ft of torque and the 18 splines are good up to maybe 900.  So unless you are building a monster engine, the 23 spline should work.  Now if you are going to be using slicks and peeling out or going to the drag strip, the 18 would be the best choice.  The 18 spline units are considerably more expensive.  I would call the nice folks at Brewer's Performance.  Try to not take too much of their time and have your questions ready.  They know just about everything there is to know about these transmissions.  I would spend some time studying their website first.  The suggestion about going with the 70's up 10.5 inch clutch/bell housing/flywheel is a good one.  Those parts are cheaper.  I like Centerforce for the flywheel, pressure plate, and clutch disc.  Brewer has reproduction aluminum bellhousings.  The transmission crossmember changed in 70 so make sure you buy the right one.  Unless you have a manual shift car now, you will need all of the millions of other parts like clutch pedal, z-bar, etc.

[440charger68]

Thanks for the info