What heads do you have???Do they have a little sybol cast into them that looks like a camels back,two humps on a block and no acsesory bolt holes???If not really we need to know what valves ya got in your heads,if ya got little 1.72 valves and we recomend a cam thinking ya got 1.94 or 2.02 double humps you'll end up with a torqueless pig that also can't rev.Take a valve cover off and look at the last three #s of the casting # ,look them up at www.mortec.com that should tell ya a little.
As for compression I dunno.But if they are no-double humps I would assume an 8.5:1 ratio(as this is a typical non-Hipo ratio) for cam selection and 9.5:1 with double humps(if they are origanal to the motor).
I would say on the intake if the Z28 intake is a aluminum and has no EGR valve use it,if not get a performer eddy.
As for Ramshorns etc....I wouldn't use anything less than blockhugger headers.For street I would keep any headers in the 1 5/8 pimary range any bigger you give up lowend torque.
For a street motor with 3.08s I say the TH350 will fit the bill great.The only reason I would use a TH700r4 or TH2004r is if I had a real nasty gear that needs to be calmed down on the highway.These trannys are expensive in comparison to the TH350.