Halfshafts for IRS: solid or tubular?

[wilf leek]

Hi guys - the following is only pertinent to Jag rear ends, but I guess it is generic enough to be worth posting.

I have a friend here in the UK who drag races. He puts 750Hp + through a std jag rear end. After 4 passes, he measures the twist or "set" in those solid halfshafts - after 1/2" of twist he throws them away and fits some new (secondhand) ones.

When building my own car, I asked a driveshaft specialist for advice, we decided to uprate the half shafts/yokes/UJ's on my rear end. Mainly because those half shafts are the only thing keeping the rear wheels in position, and I wanted it to last for more than 4 passes!

What they did was to replace the original solid shafts with tubular items, telling me that "tubular shafts are stronger than solid".

Conventional wisdom here in the Uk is that a std Jag rear end is reliable for up to 450hp, after that the UJs etc need uprating. As another friend who fitted a blower to his cobra has found out.

HTH