Originally Posted by MassiveMods

As Previously Mentioned the Rod and Crank tolerance change was made during the Gen 5 phase of engine build. The Part number remained the same till the Gen 5.5 was released then the same rod was changed in part number. So there is no need for Humble Pie , the information that was given is correct.

The fact that you tried a 21-0600 and found it was sloppy means its a larger diameter than the original 28-0600 illustrating my point , id say the rod you had was before the tolerance change , the way to tell other than measiuring it is to look at the bottom yoke and lightening groove , the 28-0600 the groove dosent square off or it may have no groove at all , the newer ones with larger bottom yoke does.

NOW realise that the 28-0600 is still in production but its been relegated the number of the RTR Rod , its not meant to be in the GX or MG range of engines. . It shares the new dimensions changed in the range of rods and crank pins.

I hope this clears things up.

Cheers MM