Strength of a a-833 with a 25 spline output

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bbab3

bbab3

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I have a '67 barracuda I am putting together with a 340, 25 spline 4-speed and a 3.50 9' ford trac lok rear. And I have some fears that the smaller output shaft used on the early a-body a-833's with the smaller 25 spine 904 yoke will handle power, am looking for approx 375-400 hp. should I up grade to the bigger shaft, or will the smaller one work and not die? The owner of brewers has told me he has seen them twist. But from how much abuse, and hp? Has any else seen this happen?
 
Ive seen 904 equiped drag cars carry tires and run mid 10's and they haven't said anything about twisted output shafts. If you are not going to use slicks and don't side step the clutch @ 6,000 I believe you should be fine.


Chuck
 
I just grabbed this out of a link on Mopar 4spds.
Strength Considerations

Chrysler engineers decided that Hemis required a beefier input shaft so the standard 23-spline shaft was replaced with a beefier 18-spline unit and a larger input bearing was used to accept the additional torque. Later Chrysler decided that the high performance 440s needed this beefiness as well. It is one of a few aspects that set the "Hemi" four speeds apart from the standard 4.35" A-833s as being extra beefy. As far as strength is concerned, outside of the input shaft, the input bearing, the retainer and some special gear sets, there were no additional measures added to A-833s for Hemis. In the Sixties the only other difference between a Hemi A-833 and a Slant Six A-833 were the gear ratios used. The Slant Six 4-speed is just as beefy as the Street "Max Wedge" V-8 units.

Mike
 
I ran 11.30's 1/4 & 7.00 in the 1/8 w/ 1.49 to 1.55 60' time in my '70 Swinger w/ 10.5 x 28 x 15 slicks with a 23 splined A-833 4 speed...Never had any front shaft problems...Sure had to buy the good rear end pieces though...LOL...Lee
 
I mistakenly bought a A-body four speed that had a 25 output shaft off of E-bay. There is considerable difference in diameter between the 25 spline output shaft and the output shaft my 69 four speed had. It would make me nervous to run the smaller diameter output shaft.
Rod
 
rklein383, below is a link on 833s that may help you identify trans you bought and probably any question you'll ever have about 833s. Mike
 
I just picked a 25 spline trany out of the neighbors barn.It was behind a 340, around 350 hp. The output shaft is broke. He claims a broken trany mount caused the break.
Could be, but I wouldn't trust one, this shaft snapped like kindling.
 
I appreciate everybodies info on the small spined a-833's. It confirmes what I thought, that mopar engineers saw the need with the intro of 340s and 383s in a-bodys. I knew about the amount of power that can be put through a 904, but its a whole different trans. It looks like am going to spend the money I saved on the rear end up grade on the trans and switch out the shaft and housing. - THANKS
 
i had the earlier 25 out shaft in my a833 bent it once driveshaft fault, then snapped one manufactures fault now have a 29 spline output. take my advice take no short cuts on your car ive stopped taking short cuts i got bit in the a** tooo many times.

just my .02
 
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