[DeTomaso] For sale, 351C crank...

[Garth Rodericks]

Cool.  Your crank looks just like my Pantera crank after spinning a rod bearing into pumice:
http://www.banzairunnerpantera.com/images/techinfo_img/engine_040.jpg

Although my "rod knock" was the sound of the crank counterweights hitting the underside if the piston skirts:
http://www.banzairunnerpantera.com/engine_teardown.htm

Time to stroke it!  Don't know if you can save that crank or not (probably not) but by the time anyone spends the money to check out that crank and R&R it, you could buy a stroker crank for just a few more dollars.