Yes, they will probably work but there is a process to go through to check for the correct length. I would start out at the number one cylinder when it is at top dead center. Slide the pushrod in, install the rocker, as you hand tighten the bolt on the rocker rotate the pushrod with your other hand. You should be okay if you get resistance before you tighten the bolt all the way down on the rocker.
Next you have to check location of the roller tip on top of the valve to find out if you will need shims.
No, they will not work. Stock pushrods are around 6.272" (I think), but the TW heads require around a 6.7" pushrod. And if they're not an old set of TW heads that were still pedestal mount, you'd need hardened pushrods because of the guideplates with the stud mounted rocker arms. Pick up an adjustable pushrod and measure the correct length.