driveshaft

[ir3333]

for those using a 904 behind a warm smallblock with an 8 3/4 rear axle.
how will the 904 and 7 1/4 driveshaft hold up if shortened?
that 904 yolk and universal look awfully small.

 

[Bad Sport]

for those using a 904 behind a warm smallblock with an 8 3/4 rear axle.
how will the 904 and 7 1/4 driveshaft hold up if shortened?
that 904 yolk and universal look awfully small.

They are, but I haven't had any issues yet. I regularly do 50-100 ft burnouts with mine and it has held up fine. If you're concerned throw a driveshaft loop under it in case it does break, I did.

 

[sireland67]

Good u-joints (spicer) you should be fine.
The main thing to look out for is the size of the u-joint.
Most 904 output is a 7260 size and the 8.75 input size is 7290.
Brewers has the measurements on the web site to identify which u-joint you have.
They also have conversion u-joints.

 

[tekslk]

I have 407 hp at the rear wheel and I use the small ones. Never had a problem but make sure there good and have driveshaft balanced.

 

[Supershafts]

See your local driveline shop and have them put in spicer 5-789 or spl22-8x when they modify the shafts length.
The 7260 is rated around 1600.ft lbs, in spl its more like 2000.ft lbs

Mopar used 7260 in everything including 1 ton trucks, 7290 is the rarer joint and the 5380 even rarer still of the 3 series they used until detroit went out.

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