Triumph Repair: spitfire questions, trimph spitfire, ford race cars

Question
hi i have 2 questions, the first one is there any interchangable rims with a trimph spitfire 1500, i need a wider rear tire ever since i swaped an RB20DET engine and tranny(skyline). also was wondering what the rear diff is capable of handling horsepower wise?

Answer
Miguel,

The only cars that I know of that used the 4x 3.75 PCD of the Spitfire are:

Triumph Spitfire 1962-1980
Triumph GT6
Triumph Herald
Lotus 7 and possibly Elan
various vintage Formula Ford race cars

There are wheel makers that will custom drill the rim for the Spitfire pattern.  Diamond Wheels was one such company.  If you have a particular wheel you like it might be worth checking with the manufacturer (or their local rep) to see if a custom drill is possible.

As to how much HP the rear diff will take?  The Spitfire diff originated for the Herald (35hp at the time) and was upgraded during the GT6 production run.  The same diff carrier was also used in the 4 speed TR7s.   

So how much HP can it handle?  The vintage racers are running 150hp+ through it.  It's more a question of how you treat it.  Dumping the clutch at redline with the Nissan drivetrain will probably get you a lot of noise and no go.


Cheers,

Jim