It's obviously of no use to you now, but when I did my timing belt, I spent half hour trying to get to that tensioner bolt with the AC compressor in place, with no luck. Then I said to myself, if it's this hard trying to loosen the bolt, how on earth am I ever going to line it up properly when trying to reinstall it? So I removed the compressor, and everything was in plain view.

I hope you get that bolt out with some heat. And don't worry about having to spend the extra time - these old vehicles, with some corrosion over time, can always be expected to throw you a curve ball like this, turning a 2 hour job into a weekend.

The worst example of this I ever had was my GS430's O2 sensor. All the forums made it sound like a 2 hour job, which it would have been had my sensor's hex not become rounded off during removal (and that's using the proper crows foot tool). I'll spare you the details, but over the next three weekends I kept upping my game, from torches (no use) to welding the O2 socket onto the sensor. The latter did give me enough grip to finally turn the sensor - and what came out was the sensor, minus the threads, which were left inside the manifold, completely galled in place. Removing the manifold for repairs meant lifting the engine, which looked like another full weekend of work. I finally tracked down a large enough helicoil set, drilled and tapped the manifold in-situ (no fun at all), installed the helicoil, and called it done. Probably invested a total of close to 20 hours into the job.