i have an 84 vanogon.  1.9, water cooled.

i've been told by more than one person that i have a warped head gasket 
and air is escaping into the coolant system.

my options: a)have this engine repaired ($ ???)
            b)get a rebuilt engine ($2055  +   $700  +  200)
                              (2.1l engine + install + exhaust conv)

questions:

is this a common problem with this engine?

i've only had one person tell me i need an exhaust conversion.  do i?

which is the better option?

if i go with option "a" what is the liklihood of having the same problem 
later?

if i go with option "b" what is the liklihood?

thanks in advance for any help you can give.

david