quench chamber heads with two barrel size intake, exhaust ports and valves. build a streetable bogus boss 302 with these heads, pump up the compression on your 351M or 400. use your 2 barrel valve train with these bare heads. standard quench chamber 4 barrel cleveland heads make good compression but low end horspower and torque suffer due to the oversize intake and exhaust ports and valves, two barrel heads will drasticaly increase low end torque but are low compression heads. with the austrailian heads you get the best of both worlds, higher compression and low end torque and they also flow well at higher RPM's, the stock 2 barrel heads have larger ports and valves than most all other small blocks. a stock 2 barrel intake will work with these heads or many of the major intake manufactures offer a reasonably priced 4 barrel intake to use with the 2 barrel size heads. these heads are bare and i guarantee no cracks. $300.00 or best offer.