273 Rockers on a 360

We used 273 push rods on Eddie's 340 when we put it together and did not have any issues with the push rod hitting the hole in the head...

After many tries to get the proper length push rod, we went to OE Pushrods and they made up a set in a few days cheaper than most off the shelf push rods...

Home - OE Push Rods - Manufacturer & Distributor

The issue is you have to give ball to ball length, not overall length when specifying the length of the push rod... That can be a little more complicated when you have a ball at one end and cup at the other...