Toyota Repair: 1990 Cressida head gasket, head gasket, radiator cap

Question
I have a 1990 cressida with 175,000 miles on, to my best knowledge the engine has been rebuilt about 50,000 miles ago. During the past week or so my heat in my car seems to come and go, especially at low rpm. I haven't noticed any leaks, but my coolant kept going down. On my way home tonight the car was doggy, i had to feather the throttle at stop lights to keep it running, a couple blocks from my house it started smoking like crazy(billowy white smoke). So I was thinking it must be a head gasket, but it also is building up alot of pressure in the system. When I got home I topped off the radiator and started the car without the radiator cap off, and it started blowing coolant out like old faithful. Could this be a head gasket, or a head gasket with some other underlying problem? I sure would appreciate any help I could get.

Answer
Yes these are definetely signs of a headgasket problem, these cylinder heads are pretty tough and are not prone to cracks, they normally leak at the #6 cylinder so when the head is removed if there is a sign of leaking on the #6 cylinder area check to make sure the head is not warped from the heat, if not, just replace the head gasket.