wait for the pro flo 4 systems to be back in stock unless you have it or a line on one .
dont do a sniper unit .
and as said 4 bolts per side = vortec 96-00-03 sbc heads
and 6 bolts per side is 95-older with tbi/tpi heads pattern or old std pattern .
vortec heads flow best over std sbc heads . 64cc chambers for little more comp ratio .