okay so just thought I would finally give y'all an update, sorry I know it's been awhile. I think what happened was that sometime before having replaced my head gaskets the engine "hydrolocked" from there being too much coolant in one of the combustion chambers; I just kept cranking the engine and using starting fluid until it started. I believe this bent one of the rods so finally one day after having finished redoing the heads and having driven the Landy around the rod broke, spun around hit the camshaft breaking it causing a piece of the camshaft to get loged in the engine in such a way that it jammed the engine up so that it wouldn't even crank. Consequently one of the lifters fell out of its place, because the cam that it rode on had been busted out by the broken piston rod, got ground into the front of the oil pan by the crankshaft counterbalance thus gashing a hole in it allowing the pushrod to fall out of the bottom of the oil pan (hence the "defender blows a pushrod idea"). Of course the lifter and broken rod also took a chunk out of my crankcase so I had to get a new engine block. Secondly! I managed to find a brand new 4.6L Land Rover block so I swapped that in, kept all the good parts off my old engine (heads, other components, etc.) and now the Landy drives better than ever and I love it again! Another thing! I kept reading all this stuff about how I needed to rechip my ECU because of the longer ****** of the 4.6 vs. the 4.0 and spend +-$1000 on a little ECU chip just so the engine would run better but now I think that's all a bunch of BS! I have not rechipped my ECU and I will tell you those looking to upgrade their '97 D90 to a 4.6, my D90 runs great with the original ECU! Has quite a bit more horses. So all is well with my D90 now, just gotta figure out how to transfer a 4.6 plenum on to my 4.0 Intake manifold so that when I pop the hood it'll actually say what kind of engine it has. Thanks all for the advice & help.