Bloody impact wrenches!!

So, it's 3:50am when I start writing this and I've spent probably the last few hours looking through hundreds of air compressors, air impact wrenches, corded impact wrenches and eventually ended with me trying to find the one I hired as a comparison.

From what I can tell this is the one I hired (although it does look a bit different): https://www.sitebox.ltd.uk/product/MAK_6905B/makita-6905b-impact-wrench-square-drive-110-volt-only/


The important thing here is the torque value which is 294Nm. Now the cylinder head bolts should not be that tight; meaning this impact wrench should've done the job!!!

Most air impact wrenches (especially those within the price range) have a torque of 310Nm which is hardly any difference!! There are ways of slightly increasing this by over pressuring the line but it will likely not go above 350Nm. I'm starting to become very concerned that I may buy this compressor and wrench and still not be able to remove the bolt!!

It's starting to seem like alot of money to risk, especially because I wouldn't be able to take it back. I'm now considering buying a super long breaker bar instead. for example:
http://www.ebay.co.uk/itm/SEALEY-AK7302-Breaker-Power-Bar-1-2-Drive-EXTRA-LONG-/180625375799?pt=UK_Hand_Tools_Equipment&hash=item2a0e1c8237#ht_2112wt_905

Cheaper than both of the other options by far, I can apply more torque through that than any of the tools we can afford to buy.. however remember how with manual tools there is the increased risk of shearing and also if I slip with a breaker bar that long I will most certainly round the bolt. Buying a longer bar was infact my first plan but I could only get a bar not even half that size and my normal 1/2" breaker is meant for tyres and has a curved neck (this is what caused me to slip and slightly round the bolt).

The more I think about it the more I am sure that a big breaker bar is the way.. it will either work.. or it'll totally fuck it up. If I find after trying this it doesn't work still and I somehow dont manage to destroy the thread I think I'll go for the cheaper electrical corded impact wrench I mentioned: http://www.ebay.co.uk/itm/1-2-Corded-Impact-Wrench-Kit-1000W-230V-Clarke-CEW1000-/400222954478?pt=UK_Home_Garden_PowerTools_SM&hash=item5d2f25a3ee#ht_3350wt_942




So I've kinda gone full circle with the idea now.. It's a shame as I'd really like the compressor etc.. but if I'm not 100% confident it will do the job it's probably better to take a risk with less money on a huge ass breaker bar!!