T5 Transmission mount rear height?

[RDMG]

Hi folks,

I have my RV8 engine and Mustang T5 trans in my 79 B for the first time, and I'm realizing I have some unanswered questions.

I can already tell that I have to ease the top of the trans tunnel and remove the stock heat shield to bring the trans up a bit, but I don't know how much it should go up.

Using the welded-in crossmember as a reference, when my trans is resting on its rear mount, what should the distance be between the bottom of the tail housing and the top of the welded-in crossmember?  Or should I be measuring the angle of the trans somehow?  

I'm using D&D engine brackets with standard circular RV8 mounts. With a D&D bellhousing spacer, the ford T5 rear trans mount sits directly above the stock B trans crossmember.  I plan to cut off the stock trans brackets on the MGB crossmember and adapt a stock mustang trans mount to fit.