I feel like you'd be cutting a hole in a new pair of jeans to patch a hole in an old pair.
If it aint broke, don't fix it.
I was following this thread for quite some time until maybe the last 8 pages. Did I miss a post? Did you find out, without a doubt, what was wrong with the current engine? If not, then that's ALL the more reason to leave this one alone. I think you deserve more time behind the wheel and less time behind the wrench at this point.
BTW, your name came up at RC this weekend. It's been quite a while. I hope life is good for you in MI.
Mikey