The hose does look broken. No biggie. You can use regular vacuum hose as long as it's a snug fit. Originally it had a stiff plastic hose with only enough rubber hose for unions.

That's the switchover valve. The bottom nipple should connect to the ALDA.

That's the ALDA.

That's not the original shut-off valve. My replacement shut-off valve is plastic too.

For the link, contact a user who goes by gsxr. That's his website.

BTW, there is no banjo fitting for the boost signal system in an 87 300TD. There's a barbed fitting the screws directly into the manifold, not through a banjo fitting.

Sixto
87 300SDL