Re: So many questions
EECIV and EECV are the engine control computers
EECIV was EA to ED
EECV was EF/EL
Main difference was the EECV is able to control a BBM (Broad Band Manifoldm, has long and short runners), were as the EA to ED had fixed length runners.
Diff Ratios are in simple turns the number of turns the wheels will do compared to the tail shaft, so 2.77:1 meand the wheels have done 2.77 turns and the diff 1 turn, so the high the number the more the wheels turn per tailshaft turn, hence the faster you can launch - strangley the high the number the lower the ratio so 3.45:1 is a low ration and 2.77:1 is a high ratio (that i know, why though I have no idea).
If you change the diff ration just bear in mind that the speedo will then be wrong, and a new speedo gear would have to be put in to correct the speedo, unless you change to a really low ratio like 4.11:1 in which case a little black box would be needed to convert the speedo signal as no speedo gear exists to correct for that ratio.
eafalcon.com has alot of specs that might help.
I did put something here, but it vanshied, I think
"So long and thanks for all the fish!"