Sorry, but a little of topic,
I had a 1977 LX 4.2 4 Speed [M20] SL Torana in Mandarin Red, Purchased it for $5,500 in 1979 with 40,000 k/s on it,
In the time I had it, I killed it a few times,
Repaired Gear Box a few times, replaced the clutch as few times, replaced the Diff from a single spinner to a LSD,
And after doing all that, and realizing I am blowing money away.
I put a set of extractors on it and got a beautiful note out of it, not loud, just a nice deep V8 note, and ended up selling it for $4,600 with 90,000 k/s on it.
Only if I had a crystal ball, you can guess the rest.