I do have shrouds. Yes mandatory now!

Here are the Whipple pulley studs. They all have to have vent holes in them. The silver alloy stud is the one that Eddie installed latest. The black ones are the ARP versions that were supposed to be unbreakable. Apparently they did have some bad ones, as the one that is broken failed in several hours of operation at about 3500 rpm @ about 3psi boost. I don't remember how much they were but were definitely 60 plus dollars. And the blowers had to be pulled to replace because of the limited amound of room in front of the pulleys.
The studs just stay in the shaft because of opposite rotation of pully's and thread direction! The new designed pulley stud has an extension into the shaft that bottoms out and relieves the rotational stress on the threaded area. If you look at where the one broke the redesigned stud makes sense. And the tapered design will also relieve stress. The alloy of the black ones has very little mass, don't know what it is but would remind you weight wise of an ARP head stud. The new ones alloy is a lot heavier, don't know what it is made from. Cost is around 100$ paid over $100.

skidoc Out in left field here but why did you have it for sale ?

Someone in my family needed financial help. I found another way to help them. Thankfully

Excellent

Thanks for posting the pics Doc. Are the better studs sold by whipple or eddie young? Thanks.

Eddie is a dealer for Whipple. I'd recommend you getting them from him, he'll know what you need and give you some good advice.....

Is this an issue on the 3.3's also or just the quad?

I can't speak to the 3.3 although I believe they have the same snout.

The studs are offered by us, as we had them built specifically to our specs. Over the years, there were multiple upgrades and the studs were just one of them. All of our drives come with the standard ARP stud and double keyway.

All high HP applications such as quads get our heavy duty drive snout. The heavy duty drive snout uses a different material shaft, offers a tapered shaft for better torsional twist, HD stud, welded pins, upgraded front bearing, dual keyway. We have never broken one of these, even at 2000hp.

The HD drives are backwards compatible.