4-Spd TL and Diff Case (C4AW-4025-C large bearing single rib) CLb Torque Limits

[Silver Bullitt]

I presently have a C4AW-C differential case (large bearing, single rib) built with solid spacer (instead of crush sleeve), 31 spline Eaton Truetrac, and 3:25 Ford gears. I'm running 205/70-14 street tires. Street driven, not drag raced.

I realize the 3:25 gearing ads to driveline stress.

Generally speaking what crankshaft torque and horsepower will the C4AW-C large bearing, single rib case support?

Generally speaking what crankshaft torque and horsepower will a 4-speed toploader support? (28 spline / Wide ratio)

I'm asking the above because I'm putting out 362+ Clb-ft @4,200 and 360+ Hp @ 6,200. Those figures were before having my carb. fully tuned. I'm finding out today I exceeded the clamping force of my clutch rated at 400HP (manufacturer will NOT give me a torque rating) and it got me thinking what driveline upgrades should I consider so I don't have additional failures...

Thanks for help.

[427heaven]

From personal experience I would say 500 plus horsepower with no problems, because the weak link is the tires not the trans. When the tires are burning,slipping,squealing,there is not too much stress on the trans, where you get into trouble is when you start adding traction devices and slicks. Street cars on street tires no need to worry, even with any gear ratio. The burnouts are just longer between shifts with tall gears.

[gt350hr]

   +1   You will be fine at 500 hp or less.  "Dumping the clutch" as in drag race starts is what breaks parts when the rear tire traction is good enough to not spin them.  You would likely spin your small tires which is "actually" easier on the parts that not spinning.
With 50+ years of drag race experience , I've seen and done a thing or two.

[Silver Bullitt]

That is good news. Thanks for input!