So, the story goes.... Some time ago, I picked up another flex plate to replace the old one. The old one appeared to have all of the bolts welded in place and I thought maybe that was the reason for the most of my engine noise. I nevergot around to replacing it. Eventually, I went for another motor; I'm in the middle of that now, with thenew flexplatee installed. What I found with the old flex plate... Only one bolt was welded in place, the other three were lose and the flex plate was cracked around the circumference of the crank bolts. So the old motor is probably perfectly fine.

Anyways, with the new flex plate, I was only able to install 3 of the four bolts with threadlock. The fourth bolt would not go in; I will assume, this is the one that was previously welded in place. With that... Do you think it will be sufficient enough , at least for a while, with the three threadlocked bolts? Until I can figure something out for the fourth?

 

No. Fix the fourth bolt. Clean it up by running a tap through.

Running with only three bolts will make it sound unbalanced. And possibly stress it enough to cause more cracking.