Depending on where crack is, it can be welded. The welder needs to know what they are doing or they will make it worst, The only difference Ihave seen between the A1 & B1 internaly is the crank of the A1 is cast and the B1 is forged. All of the parts interchange. No a b-series head will not fit an f-series block. Water and oil passeges don't match nor does the bolts line up. If you have a cracked head in your Accord, I would eather get a H22 engine complete or get a H22 head. The main resason the H swap is so popluar in the Accord is because cost and eas. The H22 will bolt to your Transmission. That means no axles, or special mounts and easier to wire. All that is needed is a V-Tec jumper harness and a ecu to make it work. Some guys use their stock ecu chiped and use a MSD RPM switch. I don't suggest this, as the VTec ecu adds extra fuel at the crossover point. An Apexi AFV-C can be used instead and can perform the same fuction. Still it is better to get the right ecu. The P28 is the universal tuner ecu. It can run any Honda engine when chiped for it. I hope this has been helpful to everybody here.