Head and Intake Question

[Chevy454]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbojet427</div><div class="ubbcode-body">I got two quick questions. First, when did the 291 big block heads come into production? Were they produced in 1969 or did they start in Jan. of '70? Second, I seen a 163 intake with a date code of 12345678 on the underside of the intake. I don't remember if it had . (periods) between the numbers or not. The intake did have the Winters snowflake casting. Very original piece. Any idea what that date means? </div></div>
I have an 840 head dated <span style="font-weight: bold">F 7 9</span> and a 291 head dated <span style="font-weight: bold">F 10 9</span>, which are about 3 days apart...so I'd say that the 2nd week of June [1969] would be close to the switchover.