LA 318 w/ Magnum Heads What Pushrods

I had heard somewhere that 351W pushrods work for the magnum head conversion. Unsure what year(s) apply there. That might be where I got the 7.650 length? I remember searching thru a pushrod catalog when I did my 1st magnum head conversion and just went with what worked on the 1st engine when I did my 2nd.
I remember buying the MPs and them not working for me, I advertised them on one of the forums and it didn't take long for me to find a taker for them. Around that time i'd seen others on the forums that had done the conversion before my appointment that had said that they had to go with the same pushrods that worked for me