My 26 Pick-up was having a loud knock when decelerating. I was hopping I could get lucky and remove a shim or two...WRONG
Well, I'll add new rods and caps to my Christmas wish list!
You may be lucky, your not into the steel yet!
Check your crankshaft. It must be smooth and not tapered or the new babbit will not last long.
Norm
Crank journal roundness is more important than taper, and more likely to be found on an old crank as well. You can live with a little taper, but not out-of-roundness.