Slant Six Forum
https://slantsix.org/forum/

3-speed ratio interchangability?
https://slantsix.org/forum/viewtopic.php?t=39461
Page 1 of 2

Author:  accomotors [ Thu Mar 18, 2010 2:58 pm ]
Post subject:  3-speed ratio interchangability?

G'day all, my name is James and I am a new Slant6 enthusiast from Australia. My dad has told me a lot of great stories about his youth when the Slant6 was a real performance icon. I am interested in building up an early Valiant Slant6 and using it for occasional historic track days, and am looking for some information. I have to have the car as original as possible (maintain original transmission type, number of forward gears as well as column shift). I have searched the forums, and found heaps of information, plus it looks you guys really know your stuff! Please forgive any obvious/already answered questions! All this being so, my questions are as follows:

:arrow: The Australian Valiant I am looking at came originally with the 'A-903' transmission with the somewhat untrackable 2.95 first gear. This gear would be too low to use for all but the tightest corners, which limits me to essentially 2 gears and decreases enjoyment factor somewhat! Are there any of the A903 transmissions (or gear sets) still around that utilise the closer 2.12-1.43-1.00 ratios as found behind the 318 in America?
:arrow: The above being possible, this still presents a problem. The A903 is non-synchro first which increases the likelihood of me mucking up a down-shift and crunching. Is there any way of fitting a synchro out of an A230 or similar (or machining the shaft to accept one as I read you can do on reverse) so that I could use first more readily?

I guess what I'm saying is, is there any way to get the tallest possible factory gearing in a 3-speed column all-synchro Chrysler box? (Yes, I want my cake and I want to eat it too :P)

Author:  sandy in BC [ Thu Mar 18, 2010 3:10 pm ]
Post subject: 

Im sorry....your accent confused me....did you say you wanted a 5 speed?

Author:  accomotors [ Thu Mar 18, 2010 3:14 pm ]
Post subject: 

Hehe, sorry. Must be the kangaroo I had for breakfast!

Nah, I want it to be a 3-speed, column shifted, factory Chrysler box with the tallest ratios available and synchros.

Thanks for the prompt reply!

Author:  Joshie225 [ Thu Mar 18, 2010 4:53 pm ]
Post subject: 

I'd use an A230 and just rework the existing linkage if you need the syncro 1st gear. Big block A745 transmissions had 2.55, 1.49, 1.00 ratios which is about as close-ratio 3-speed as you're likely to find. I don't have a list of A230 ratios.

Author:  DusterIdiot [ Thu Mar 18, 2010 5:52 pm ]
Post subject:  Not going to be his favorite

The mid-70's ratios were stuck at:
1)3.18
2)1.77
3)Direct

The early versions behind V-8's could be: 2.55,1.49,1.00- but how to identify one in a junker would be a new one to me...

The A-903 I think was 2.55,1.49,1.00

-D.idiot

Author:  Joshie225 [ Thu Mar 18, 2010 6:11 pm ]
Post subject: 

The A903 behind a 225 is supposed to have a 2.95:1 low gear in 1966 at least.

Author:  Exner Geek [ Thu Mar 18, 2010 6:23 pm ]
Post subject: 

It's been a while but I seem to remember that the A903 in 1960-61 had a 2.71 first gear. I believe that 1961 225 Lancers had a 2.55 first. The ultra rare Daytona cars were supposed to have a 2.31 first and a 1.55 second. In those years the transmission was tilted over 30 degrees but the I think the internal parts would interchange with the 1962 and later straight up and down type. All these are non-synchro which I can't imagine downshifting. Good luck.

Author:  accomotors [ Thu Mar 18, 2010 7:11 pm ]
Post subject: 

Thanks everyone for your replies! The page I gathered my information from is below:

http://cjford.stormloader.com/Tech/mantransinfo1.htm

If such boxes are rare as you have said, perhaps using one with a 2.55 first would be the way to go (A745?)?

Author:  Doc [ Fri Mar 19, 2010 5:51 pm ]
Post subject: 

The reason these transmissions are hard to find is that most get thrown into the scrap pile.
I have a few around but I don'r know what the ratios are.
In the end, you still have a non syncro 1st gear... there is no way around that.
DD

Author:  accomotors [ Sat Mar 20, 2010 10:06 am ]
Post subject: 

No way around the crash first, oh darn. So lets say I don't want standard, are there ANY all-synchro, 3-speed, column changed Chrysler boxes that will mount behind a slant?

Author:  DusterIdiot [ Sat Mar 20, 2010 12:18 pm ]
Post subject:  1970-1980

Quote:
So lets say I don't want standard, are there ANY all-synchro, 3-speed, column changed Chrysler boxes that will mount behind a slant
The A-230 is the other choice when looking for a synchro box...

Author:  accomotors [ Sat Mar 20, 2010 3:28 pm ]
Post subject: 

Ah ok, I figured there had to be one. How different is the A230 to the A903? I take it from Doc's post that nothing is interchangeable?

Author:  VG-265 [ Sat Mar 20, 2010 4:16 pm ]
Post subject: 

Old Car Gear Boxes Pty. Ltd. in Moorabbin Vic can probably do what you want.
They can do new gear sets with improved ratios.
I would think it will be quite expensive though.
Their number is 03 95533207

Author:  DusterIdiot [ Sat Mar 20, 2010 9:04 pm ]
Post subject:  Uhhh...

Quote:
I take it from Doc's post that nothing is interchangeable?
You got a 3 speed bellhousing... take 1970+ A-230 and bolt in place of A903/A745...etc.. "done"....

:idea:

Author:  VG-265 [ Sun Mar 21, 2010 5:07 am ]
Post subject: 

BTW Accomotors, do you have any IHC stuff?
Just thought you might going by your forum name.

Page 1 of 2 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/