Triumph Repair: GT6 differential

Question
I have a spitfire that I am putting a mazda miata 2.0 with a 6 speed in. It should be a light fast car with great gas mileage.  The question is the differential.  I have a gt6 diff 3.27 that I know is alittle week for the 160 hp mazda engine, however it will bolt in.  Can I build that differential up somehow to strengthen it?  Even strengthening the case could be done. What can you suggest if anything.  It could be an answer that a lot of car enthusiast need.  We know the week spots of the spitfire.  I just like the car and would like to improve it.  I am not looking for other diff suggestions, just advice if this one can be strengthened.

Answer
Hi Paul,

I don't know what could be done to beef up the differential. Other then replace the whole rear end. If I were you, I would try to make contact with someone in SCCA that raced the Spitfire / GT-6 as the stock rear suspension was a swing axle and very dangerous to use in a turn and needs a lot of modifications just as John Delorian found out when he was at GM.

I just installed a hopped up 215 Cu in V-8 in an MGB-GT and I cut down a Ford Mustang limited slip differential to fit the car. That was a lot of work but finding any kind of rear end of the correct width was the problem.

Even if the GT-6 can handle the load of 160 HP you still have the swing axles to contend with. VW and Corvair both found out the hard way not to use it. I knew some people with Spitfires etc and they Auto Crossed the cars but had to restrict the movement of the suspension to stop the loss of tire patch contact with the road and stop the "tuck under" of the outside wheel which caused the "Roll Over" of those cars.

To change the rear syspension is a lot of work but so is what you are already doing. I think with all the work modernizing the Engine and Trans you will be disapointed in the results by leaving the poorly designed rear syspension in it.