[HondaCivic4358]

I have a 1989 CRX Si and I think I might have a blownheadgasket. There is oil in the radiator and my car is blowing out like white steamy-like smoke. The car seems to idle fine but misses a tiny bit (barely noticeabale). The car idles at about 550 after the electric choke goes off. The car does have 204,500 miles on it. If someone could tell me what it may be and about how much it would cost. Also if I would just be better off buying a newer engine for it because of the miles and the labor and cost of the headgasket (if that is what it is). Thanks,
Ryan