350 Chevy pre 1987 with vortec heads what pushrods do you use the 87 or has flat tappet cam?

A pre-1987 350 Chevy engine cannot have Vortec heads. Vortec heads were introduced in 1996. Pre-1987 350s used small-block Chevy heads that are *not* Vortec.

If your engine has a flat tappet cam (which is standard for pre-1987), you need pushrods designed for a flat tappet camshaft. The length of the pushrod will depend on the specific camshaft you're using, the lifter type, and the head gasket thickness. You cannot just use "87 pushrods" as a generic term; the correct pushrod length must be determined for your specific setup. You'll need to consult a camshaft manufacturer's instructions or use a pushrod measuring tool to ensure the correct length.