no rattle was required but now use a socket to suit with breaker bar and in the socket dab some metal shavings / debri from machined brake disc rotors from any workshop and should grip stuffed bolt heads like these enough to loosen up. Good luck and keep the metal debri in a small bottle like an empty plastic fake vanilla essence bottle, its a life saver especially out in the sticks.

You can try drilling the heads off the bolts. That's worked for me in the pasts. If the bolts have dimple in the centre you only need to drill a pilot hole the thinkness of the head. If there 12mm bolt use a 1/2 inch or a 13mm drill bit start drilling &'the head will just come off. Just like drilling a pop rivet off

Thanks for the tip D!
Coup1200, I'm trying to avoid drilling them if possible because of their hardness. That will be an option though if need be. If I remove the head it might be difficult to remove the threaded shank, and an easy out might be tricky because of the tension. Still got a few tricks to try out but I'll let you know how I go.

Nice clutch.

Get a few sacrificial sockets 1mm smaller or imperial slightly smaller. Smack them on tight and get a long breaker bar (or short with a bit of pipe over te top) then try undo.
Worked for me in past.

Toledo twist sockets. P#301521

Thanks for all your tips guys. Coupe1200, I ended up using something similar to what you suggested.
This pic shows the three culprits, funnily enough I tried to remove these already but had failed. I walked away and a few days later felt inspired to give it one last crack before getting out the drill. With a bit of help from my favourite persuaded (hammer) and the stud remover on my rattle gun, all three came out with ease!
Sometimes it just pays to leave a job for a day or two (or a week) and come at it with a fresh mind. Worked for me anyway.

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Whilst I was ignoring the flywheel bolts I took some time to get some wiring sorted out. Engine loom is run through the engine bay, ecu mounted and ready to go. I have cleaned up the 1200 loom and have it run through. Got a re-trimmed dash as well a few weeks ago so have put that all in. Cables etc also run ready for the motor.
Flywheel being machined tomorrow so hopefully this weekend will see some serious progress.

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....Finally got this in! I love the feeling of accomplishment, there's still a heap to do but it's nice when you can see real progress.

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Wow it's moving along now. Almost ready to hit the highway to Ballarat!

Latest progress. Intercooler mounted and piping done, all wiring done including main power to battery now mounted in tray, intake done, tunnel cut to fit the shifter and new rubber boots fitted.
Intercooler fits nicely behind the grille and all piping was off the shelf aluminium and silicone bends - easy.

Just need to add fuel now! First crank tonight follow this link to check out the video on YouTube. https://www.youtube.com/watch?v=PB4iMyWnTok

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