Thom

Dean pretty much has it, as far as the perches go there's only two different widths, xk-xp and xr to el, overall widths are different with xk-xp being the narrowest, then xr-xy, xa-el (there are some minor differences differences in widths but its less than 8mm and that's main due to the differences between drum and disc brakes) and au-fgx being the widest

You may as well just pull it apart, with that much variation it's not going to be fixed without at least the head coming off so you'd as well do it to know what your up against

I use a elm327 with the forscan lite app, it's sometimes painful to get connected to au's but once you do its very useful for diagnostics, ba-fgx work pretty well with it though

You are correct, I probably should have spell checked

Yes it will run hot if you spin the water pump backwards, the design of the impeller and timing cover are both to suit the reverse rotation water pump and will cavitate the water rather than pump when spun backwards, to go to standard rotation you need a pre 86 timing cover, water pump and balancer (balancer needs to be 58ounce imbalance as you have a roller cam engine, if you use a 28ounce early balancer then engine will vibrate and possibly damage the crank, you also have to use a flywheel or flex plate to suit the roller cam engine, 1986 was when the 5.0l went to 58ounce balancer and flywheel/flexplate) the early timing cover, water pump and balancer also means you will need an early alternator bracket, be aware the v belt setup makes a windsor longer than the serpentine setup but that's not a problem in an early falcon

Rod bends and twists, valve pocket is no longer below valve, flat of the piston hits a valve and bends it

Sounds like it's autopsy time, if the gauge is correct, it means that every cylinder has damage, you won't know without pulling the head off or using a bore scope to assess what went wrong, but if I were a betting man I would say you have more than your fair share of bent rods and valves, and if it is really that bad you may be better of financially to just swap the whole engine

If its winding over slow that's a good indication of bent things, unfortunately you won't know what you need to replace until you do a bit more investigation, a leak down test will show if the cylinders are still sealing, but if you've got to pull the head off anyway to change rods+ whatever else is damaged you may as well inspect the valvetrain while it's off

Compression test will show if the engine is mechanically damaged, all cylinders within 5-8% of the same reading should still run smoothly, a bent rod or valves will show lower compression on that cylinder, cylinder walls can crack from hydrolocking but you would most likely bend rods firts (and possibly damaged the skirt on a few pistons if the rod hes bent far enough to let the piston hit the crank, alternatively if the rod twisted it could have bent far enough the valve reliefs dont line up any more, in that case you would have bent valves too) and if the cylinder wall was cracked you would have water in the sump, main bearings will be totally fine unless you've managed to bend the crank but it would probably not run if you managed to do that, e series rods are shorter than au-fgx except el hybrid engines they are the same length as au-fgx, the bigger problem for swapping rods on anything but a factory turbo 4.0 is they use a press fit gudgeon pin and are quite difficult to change without the proper equipment,.you also can't put sohc pistons in a barra as the valve reliefs are in the wrong position for the barra head

Speedo sensor, gearshift indicator (sometimes referred to as neutral safety switch) and wiring loom, only external, internal wiring doesn't need to be changed

All au trans will be a straight bolt in, just make sure you use the electronics from the car as one of the years has a different gear position indicator and I can't remember which one

Ea to au btr's are mostly interchangeable, in 6 cylinder cars with another 6 cylinder btr (some v8's had sports shift like ed sprint, el gt, au ts50 etc) to use an earlier btr in an au it is recommended to fit the au bellhousing to the e series transmission (straight swap make sure you get the converter re seated correctly), the e series bellhousing wilbolt to the au engine but it won't bolt to the sump, you'll need to use the au speed sensor, neutral safety switch and wiring, ba an later btr's can't be used in a ea-au (except maybe column shift ute transmissions but im not certain on that one) as they don't physically have shift positions for 1st to 3rd and are setup to run with the "sports shift" shifter, also unless it is a ute transmission it won't have a mount for the speed sensor (without it the transmission won't shift) as ba to fgx (except ba utes) all came standard with abs and use the abs sensors to tell the ecu how fast the car is going for controlling shift points

The change in 4.0l happend in mid 98' pre mid 98 4.0 will have a 4E---- or ---DT if tickford number cast into components (easiest ones to pick are cylinder head, timing cover block etc) and will have early style valvetrain (2.1 rocker ratio straight valve springs and lager valve spring retainers) the bottom end will also have crossflow sized main bearings and shorter con rods (than au through barra) late 98 (known as hybrid in el) through au will have a casting numbers starting with WR2A---, the cylinder head has 1.8:1 rocker ratio, beehive valve springs smaller valve stems and smaller valve spring retainers, the bottom end has larger main journal's, longer con rods, a girdle and in au will have an aluminium sump with the main caps cross bolted to the sump, the el hybrid engines are essentially an au engine with a tin sump, xh may have got the update later than the sedans did as xh production happened nearly a full year into au production

Do you have the sandwich plate between the block and the bellhousing, if you don't the starter spacing and position will be incorrect, if you are after a cheap hi torque starter anything from ea to bf falcon will fit crossflow

Xg are different to xf, but you still need an aftermarket sway bar for au 4.0 or barra, AFAIK tuff mounts are the only ones currently doing aftermarket sway bars, like Dean said its a conversion one, if you wanted something heavier you'd probably have to have it made, On the rear you can use a sway bar to suit xd