If you can, use the D16 rod. The LS rod maybe stronger, but its also heavier.
Re-balencing is a must.
I'd take a properly tuned D16 to 250hp without too much worry, but anything over that, and I'd have a "back-up plan" ready.
I'd trust the LS rods for over 300hp.
Really I think the D16s have a problem with breaking pistion rings or pistons. broken rods are more a " untuned propblem " IMO.
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86' snapper electric powered lawn mower.
95' F-350 crew-cab powerstroke 5-speed 21.63mpg
03' G35 6-speed coupe. Grey on black.
02' wranlger apex edition with EFI 5.0L 302 SBF. 5.5'' lift, custom 4-link 8.8 in the rear, high pinion D30 front with locker.
A wise man once said, " I didn't wash my hands b/c my D**K is cleaner then ANYTHING, in that bathroom"