Welcome to FTE, and that is indeed one of the sweetest 81's I've ever seen. Congrats on your ownership, and to your grandfather for keeping it so well.

Points to ponder ... You don't need a hoist, but the exhaust manifold is heavier than you may think. Leave at least two bolts barely loosened, you can remove the rest. Always good to poke any bolts or screws into a big piece of cardboard and number the sequence. Be certain to fully disconnect the piping.

If at all possible, have a friend (and they should be a good friend) either hold the manifold or remove the last two bolts. Give it a slight wiggle test and make sure everything is fully disconnected, and you have clearance to remove it. It is heavy enough to get away from you if you're just leaning over the fender. In other words, you don't want to let it drop down and bust something, or have trouble hoisting it up and out and busting something else.

 

John - I can't say it is definitely a Cleveland, but that is highly probable.

The plate shows the engine to be a "C", but that might not mean "Cleveland". Here the 351's were code "G", and depending on the year that could mean either 351M or 351W. I did a quick Google of Ford, Australia, engine code, and 1981 but didn't find anything definitive. Perhaps you can?

Having said that, I have George Reid's book entitled Ford 351 Cleveland Engines and did find some things in it that might help. First, on Page 27 he says: "...Ford never produced the 400 or 351M in Australia." And then "As a rule, Aussie Cleveland castings don't have Ford North America casting numbers..."

Then on Page 29 he provides these two pictures, both provided by Tim Meyer so I'm sure Tim won't have any problem with me posting them here. Here's one of a 351M/400 block on the left and a C block on the right. Notice how the thermostat boss protrudes upward on the M/400 block (the red arrow) and is even with the top of the block on the C (green arrow)? What does yours look like?







And here's a shot from the rear with the M/400 on the right and the C on the left. Notice the different tranny pattern? On the M/400 I have on the stand I measure the distance between the two holes I've circled in red as ~7", and the matching holes on the right side are ~7 1/4" apart. Can you measure yours?




Now, even if it is a Cleveland, we haven't proven that it is a 351 as opposed to a 302 - both of which were produced in Australia. And, like the M/400, I'm afraid there's not much way to tell that w/o measuring the stroke, which can be approximated with something like a straw stuck through the spark plug hole. Turn the engine slowly by hand and measure how far the straw moves. A 3" stroke is a 302, and a 3 1/2" is a 351.