Have a look on the internet I think its www.marksadaptors.com.au
They have all the info and prices for kits. You will be suprised how expensive it is.And yes the old 3y/4y is pretty gutless.
I am just going through the exercise of 4y rebuild on a 4X2 auto,The auto has been retired for a late model 5 speed the engine has been balanced, block decked,crow cam, chrome molly rings, head flow tested and polished, dgv Weber with extractors electing dizzy, complete timing chain kit, new lifters. Not a cheap deal but compared to a v6 heaps cheaper
Cheer
Dave