Im twin turboing my 289, someone told me that running that much boost (only about 14-15psi) would blow my head gaskets, ive never heard this before.  it kind of scared me because i dont know weather i should believe him or not? anyone have an opinion on this anything would help  thanks, jed

If you have enough boost the gaskets will go and since it's a 289, then it has a thin wall block.  If you were to o ring the block or heads that would help but you're still limited because of the design.  If you were to keep it down arould 10 psi, it'd live longer but even if you o ring it, they'll still blow if you get crazy with boost.