Here's my '69Z.
JohnZ's heat riser appears to be mounted (as I view it) where the weight is pointing towards the RF wheel well... (NOT towards firewall).
Someone referenced the AIM.. I've searched thru it, looking for a view of the heat riser,and could not find one. What section/page is this located in?
and to respond to another comment: Yes, Z28's have/had headers (or 99% did) within a few days of delivery, as that was the intention of the engineer who conceived/designed the 302...
.. it's only now that we are all striving to 'restore' to factory configuration..