Here is a set of 289 hipo heads for sale. Date code on the heads are 4H3 and 4G23 and marked 19 and 20 on the corner. These heads are complete and with springs, valves, screw in studs and push rod guide plates. They came off of a running motor. Date code is too early for my project.. Price is $1500 plus shipping. Email tscarano1@hotmail.com for pics if interested. Thanks.