the vtec oil pumps and the b20 oil pumps are a bit higher, but it shouldn't make a difference. This happened to a friend of mine. Double check your timing (cam and ignition), and if its not off, take your cat off and drive it around like that, and check to see if you can see through it, if not, smash the internals out (or buy a new one). Its cause when it goes into vtec it gets choked off by the ****ty old cat. At least, thats what happened to my friend....