I think he has the message now. The simple fact is that a well engineered car is a matter of balance, You use the component that will do the job that you need it to do, but nothing more.

The Bluebird diff center should provide you with a 3.9 to 1 ratio in the 1200 Ute rear axle housing. You may eventually break it if you really try hard, but for regular hooning about, it will serve you well & long, after all, it is what is used in souped up Bluebirds, & they are heavier & have 2L engines.

The Hemi in my 33 coupe will be good for about 325hp in a 25cwt [1.25 toonies] car & even then i will not use a 9" Fraud rear axle. I'l use an 8-3/4" Chrysler one.

Whats the word?..................Balance.