HI im looking at changing my gearbox and diff from a ty752vbcba to a ty754vbaaa the fifth gear on the 752 is 0.825 and on the 754 its 0.738 .my question is which box would have lower revs at 70mph if that makes sense all help greatly appreciated as the cars been off the road for far too long

 

The 752 box has a 4.111 diff ratio.......the newer 754 box has a 4.444

What you gain on the taller gear (.738) you lose on the diff ratio - they will be very similar if you were to plug them into a calculator.

Rgds, Ade

 

THANKS Mate been reading a little more from here on the 754 box its off a sti 5 ,and found in the p1 ,should be good for 156 mph apparently and pretty tuff too