Wow,so many answers that are just wrong....
216,235 and 261 engines,other than the rear main cap,have no dowels pins or registers cut into the block to locate the main caps.The caps are located by that shoulder just under the head on the stock bolt.Use any other bolt and the main cap location is lost.maybe the ARP bolt or studs have the shoulders....
This is not to say the engine won't run with the wrong bolts.
