[Treeve]

Having two overdrive gears is a wank... especially when 5th in a 5 speed is not the same as 5th in a 6 speed. The 5th in a T5 is 0.68:1, where’s a T56 normally has a 0.8 5th and a 0.63 6th. So you’re giving up 0.05:1 in ratio in 6th and you’ve got a 5th gear for... wank factor. The difference at your quoted 1850rpm at 110km/hr with a T5 is that you’d be doing a bit less than 2,000 rpm with all the rest of your drivetrain the same. And you’d do the same revs for all other scenarios in 1-4 gears with 5th in the T56 being the standout as not having an equivalent.
Plus the T56 weighs more. A lot more.
Interested to know what you shim to improve the gearchange though - got more than a couple of LS conversions with T56’s attached that I’d love to improve. Link to an article on how to do it?
Cheers,
Treeve