Use stock 1970 340 rods in rebuild?

Or you can just replace the rods bolts and run them as is. I always got away with that.... never a rod problem yet, in many thousands of miles of hard racing. Mind you, this was with Opel and Mitsubishi and Ford small block rods and such. I do have a set of 340 rods that I will put in a 360 at some point, with just new bolts.

If you have the $$, I favor just going to SCAT rods for around $300 a set. Ready to go, and weight matched to each other, but beware they are lighter than stock rods by around 180 grams each so a crank rebalance is in order. So there is that cost.

But if you are going with lighter pistons like KB or SP hypers, you are already going to rebalance due to the lighter piston weight. In that case, it seems like a no-brainer to add the SCAT rods: the new pistons are balanced within 1-2 grams of each other, and so will be the SCAT rods. So you buy them, give the weights to the machinist ( the big end and small end weights for the SCAT rods comes marked on the box), and the machinist uses those numbers for the crank balance alone, and you match the rods/pistons yourself. That maneuver will save about $100-150 on the balance work.