Suspension bolts - do they have to be this tight?...

As I progress in my suspension/brake/steering/timing belt winter rebuild project for my 308 GT4, I got to the point of taking apart the rear suspension, in order to replace the bushings (front suspension removed from car, and old bushings removed from arms - no problems).

The bolts (part# 106419) securing the rear A-Arms to the arm forks (these are the inboard joints) were tight, but came apart with hand tools.

The bolts on the outboard joints (A-Arms to wheel uprights, part# 105344), especially the lower bolts were the problem I encountered and I can't figure out why. The top bolts came off with hand tools, again, no problem, but the lower bolt (and I should add, this was the same for both sides of the car) were in so tight, I needed a 3/4" impact wrench (which puts out approx. 800lbs-ft of torque) to remove them and even then, it struggled! I even gently warmed up the parts with an oxy-acetylene torch (being careful not to heat too much as the upright is cast aluminum) and it still gave me a hard time. I had to work it back and forth for several minutes before it finally spun free and was then able to extract it from the assembly.

I was expecting the bolt to be covered in oxidation because of this incredible seizure (aluminum and steel don't like being next to each other!), but was blown away by the fact that the steel bolt was in perfect condition! So too was the aluminum upright! The only thing that was present seemed to be a tacky, gooey substance on the shank of the bolt.

I've included in the below attachments a scan of an FCA newsbulletin article that was published in the '70's concerning a suspension recall affecting GT4's. My car was affected by this recall and I'm assuming it had been done, so what was done, did it involve having the lower bolts covered in this sticky substance?

And if so, why? If you look closely in the parts catalogue, the bolt has no affect in suspension movement - as the inner bushing, part #109905 does this job - and therefore, cannot be worked loose from suspension movement so the bolt does not need to be "glued" in like it was. When I re-assemble, I'm not going to coat them with any kind-of sticky paste as I really don't believe they need anything like that (in fact, I'm a firm believer in using anti-seize on fasteners as I deal with stuff like this in my line of work. When used properly, the fastener stays together, but can be removed in the future!). It doesn't make sense that the top bolt could be removed with hand tools and the lower bolts needing a super-duper industrial-grade tool to remove and have a hard time doing it!

When I recondition everything (painting, plating, etc), most certainly I'm tossing these old bolts and getting new ones as I'm sure they've been stressed from the 800lbs-ft of torque from that 3/4" impact wrench. Honestly, when I was working these, I was tempted to use a 1" impact (at about 1000lbs-ft torque!) to spin them free, but I was sure I would rip the heads off the bolts and then I'd be in bigger trouble!

Thought? Comments?
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I was able to remove the nut with hand tools. The part that gave me the problem was the bolt itself.

 

I did not want to lay down too much heat as I had said, the upright is aluminum and it doesn't take much to start melting things. Believe me, I've done it before...

Even if I had gotten to the point of melting the upright, I can imagine it still would have taken some effort to remove. I stress, these bolts were in there good and tight.

 

I am going to use anti-seize upon reassembly. I still can't figure out what this stuff was (to me, it didn't appear/feel like old grease) or why it was put there...