Buses, campers, the 440's that were in Cranes etc, dump trucks--many had the six pack rods--not all--it just depends on year , application, etc but many had them--I have seen more broken six pack rods than std 440 rods over the years and more when used in race applications--I think they are brittle--just no sense in using them unless street application then they are just fine--I bought some NICE H Beams off ebay this week from dealer in Texas on Ebay--came with ARP bolts--looked very well finished--.990 pin and all $300 plus $28 sh not bad...One had big end a tad tight and as usual pins need fitting ( normal for all brands ) so there is just no reason to run that old stuff--I say that and yet we do several a month with redone stock rods--they go out and play hard--never an issue but then we are using an 880 gram piston / pin vs the near 1200 gram of stock slugs it makes all the diff.