Crank and rod help please

The 2899496 rod is a 68-73 rod,the 3418645 is a 76-87 318 rod,both having the same center to center length.As long as they weight the same,they is not a balancing issue.The 2899486 rod is a floating rod,so this means some one was in there before,mrmopartech 450 424 0445