HP limit of stock fox driveshaft and "heavy duty" 1310 u-joints?

[dville_gt]

I am running around with a stock steel fox drive shaft and will be replacing whatever u-joints it has in it with some "heavy duty" precision u-joints.

Just wondering what the hp limit for one of these shafts is. Car is an auto leaving off a foot brake which should help it live with a little more power. Right now the car is always on bias ply et streets but will be swapped to et street radials over the winter.

Any idea how much power these shafts can hold? I have a loop so I am not super concerned if it does break, but I'd like to know if I am on the edge or not.

Car goes very low 7's at around 97mph on motor right now. Looking to add a bit of power over the winter.

[BlueCoupeRedVert]

looking around google, i see 500 to 700hp.

[jw33]

With a lightweight car through an automatic it should be fine as long as the joints are in good shape with no slop at your HP level. FWIW I picked up a custom made aluminum DS with the yoke shipped to my door for around $380 a few years ago.

[Doug Hatton]

Mine's stock with stock ujoints.

[2165 Turbo Rail]

I was using the stock one from my GTO and it broke on the dyno and I only made 535 to the wheels

I was told a drive shaft is likely to break on the dyno before it would break on the street if that matters

I had a ds built and since i did the 9" at the same time I did the big ford u-joints all the way around (brain fart, i can't remember the u-joint.. 1310? 1350? 1390 something like that)

*Edit just saw the title of the thread.. mine must be 1310

[dville_gt]

I was using the stock one from my GTO and it broke on the dyno and I only made 535 to the wheels

I was told a drive shaft is likely to break on the dyno before it would break on the street if that matters

I had a ds built and since i did the 9" at the same time I did the big ford u-joints all the way around (brain fart, i can't remember the u-joint.. 1310? 1350? 1390 something like that)

*Edit just saw the title of the thread.. mine must be 1310

no, 1310 are not the beefy ones, 1350's are.

[2165 Turbo Rail]

no, 1310 are not the beefy ones, 1350's are.

then I got the 1350

[greenbullitt]

theres also a 1330

[turbostang]

Lots of factors to consider - loose converters, clutches, tires, suspension condition, suspension type etc.

I've seen stock cars with slicks break on the first pass, I've seen 1000RWHP cars with stock axles run deep in the 8's in the quarter, but I've broken them in 300RWHP cars - there's no good, solid number to go by.

Eliminate the stress risers caused by exhaust rubbing grooves, dents from road debris or who knows what, and undercut welds and it will make a difference... just keep in mind, it's running on borrowed time. Something as simple as a scratch in the driveshaft can cause it to break.

[turbos66coupe]

Inland truck parts in denton makes them for cheap. Had a friend that got one made from them 3.5" dom tubing with yokes and ujoints and went 5's for around $300

[Chas_svo]

Also make sure you put the ujoint in correctly, so the rotation is trying to compress the hole where the grease zirk is, not stretch it. The joint is much stronger this way, and I've seen them put in wrong from driveshaft shops. This probably sounds lame, but it cost a buddy about $2500 one weekend as he broke on the launch, and had the guy covered.

[dville_gt]

Also make sure you put the ujoint in correctly, so the rotation is trying to compress the hole where the grease zirk is, not stretch it. The joint is much stronger this way, and I've seen them put in wrong from driveshaft shops. This probably sounds lame, but it cost a buddy about $2500 one weekend as he broke on the launch, and had the guy covered.

no cast in zirk on the "heavy duty" model.

[2165 Turbo Rail]

Inland truck parts in denton makes them for cheap. Had a friend that got one made from them 3.5" dom tubing with yokes and ujoints and went 5's for around $300

Inland in Irvin built mine. I don't remember the cost but I am thinking it was around $400. That was from scratch with the 1350 ujoints and a yoke with thick wall tubing

[turbostang]

You have to keep an eye on ITP - they didn't have any idea what DOM tubing was when I asked and the one over by me was NOT using it.