Do you have the casting numbers of the heads? In 1967, two different cylinder head castings were used on the 302 engines, 3917291 and 3890462. Both heads used 2.02/1.60 valves. 1968 used casting number 3917291 but there’s a very subtle tell-tale - the 1968 heads have a water temperature sensor, the 1967 heads do not. The 291 castings have a slightly larger combustion chamber volume than the 462 castings – 64cc versus 63cc. The exact combustion chamber measurement of a perfect 291 casting is 63.995cc. 1969 engines used head casting number 3927186. Still have 2.02/ 1.60 valves but in1969 the heads were drilled and tapped to accommodate the new alternator mounting position. All three numbers have the camel-hump stamping on the end of the head. All three were also used on HP 327 engines as well.The 186 castings are most sought after – typically fetching $1,000 - $1,500 a pair depending on the condition.