RE: the best stock cylinder heads
the best stock cast iron heads for your 327 are the L31 Vortec heads. they outflow every stock SBC head ever made including the old Bowtie heads and outflow ALOT of aftermarket heads. the only draw back to them is you have to use a Vortec specific intake and intake gaskets. i have seen the Vortec heads make 350+ hp right out of the box. best choice in cast stock heads there is.