That isn't really a very big cam. Very little difference to the OEM 340 type grind. I think that you had better do some checking to see what is wrong. Yes, it sounds suspicious to a head gasket but not nessessarly, they are not that notorious for going out if the surfaces are prepped and torqued correctly. Very few are retorqued.
Pull your valve covers and make sure that all the rockers & push rods are in place. Also check your coolant level in the radiator.