These cars are like women. You always have to make them happy... Other wise it will tend to f....k u in the bad way.
Did you clean the block where the crack pipe slides into the opening? Also use a tiny bit of engine assembly lube(comes in a tube) on the o-ring before sliding it into the block. You probably pinched the o-ring.
Take some sand paper to knock down any scaling on the block before installing the crack pipe. That'll also help you get a nice tight fit and stop the o-ring from getting pinched.
slumz of worcester
It never hurts to brush-on a little sealant on the end of the crack pipe/over the o-ring before install to ensure a sealed fit: