Need help transferring 74 block parts into my new 89 block

Had a 74 360 running good but unfortunately it threw a rod and now I’m back to rebuilding and bought an 89 block without knowing that’s it’s a hydraulic roller cam instead of flat tappet now I was just looking to know if and how I can use the flat tappet cam,lifters etc from my 74 in my 89 block I was told something about having to send push rods to the machine shop