Everyone is Vulnerable.  My partner opened 2[heart] and my RHO passed.   I hold:

[spade]74  [heart]K9743  [diamond]Q9653   [club]3

What should I bid?

Bid 4[heart].  This is a hand that you need to bid quickly to a high level.  The opponents have the majority of the HCPs and at least eight spades between their two hands.  When your partner makes a pre-emptive bid and you have a good fit….your job is to make it as difficult as possible for your opponents to convey information.

See more of this technique in Patty’s “Weak Two Bids”.