I am looking to find out what the correct paint would be to paint my engine compartment with. I have seen many varying photos on the internet. From what I can tell so far is that the entire car was painted red oxide primer for the most part. Then the engine compartment was painted semi gloss and then the interior color and then the body color. Please correct me if my assumption is incorrect.
There are a fair number of threads related to the subject and in general 65-68 San Jose car paint process was fairly similar so you might want to visit and read those threads.
For a short (lacking many details) version
- On the undercarriage an epoxy red oxide primer sealer was applied from jets attached below the moving assembly line that sprayed up onto the body from the firewall rearward. From the firewall rearward the front frame rails and parts of the inner fender panels.
- Unibody with trunk lid & door panels was painted red oxide (other parts off the car were being painted various finishes)
- Once that was done the rear bumper guard brackets, rear valance (hung by only two screws and allowed to hang downward) and the quarter extensions. Then a light coat of light grey primer surfacer was applied
- Interior paint process was then done and then masked to protect it from the body color application that came next. This included the rear wheel wells and trunk area. The application of body color produced direct application onto the floor pans, frame rails and panels that hung or bent downward while overspray carried further inward.
- Then engine compartment, radiator support (both sides) and inner fender panels (rear splash shield attachment spot to the other side rear splash shield attachment location)
- Then the pinch weld black out from front/leading edge to the rear edge at the rear valance. This produced direct application onto the floor pans, frame rails and panels that hung or bent downward while overspray carried further inward but not typically as much overspray or inward travel of it due to spray angle and lessor gun air pressure. Study pictures of original cars to get an understanding of what the logical results would look like. Reproducing this and body color overspray with the spray guns of today take effort and planning since the results are very different
Left out the whole sound deadener (when and where) discussion in this description since you were focusing on paint in your first statement.
While you doing things you might want to check the paint details at the bottom of the doors. A common mistake by many painters
Most use single stage in the engine compartment but because of laws not everyone can get or shot everything. Suggest you do a search and read one of the dozen or som threads on the subject.
Very little to no primer was used in the engine compartment. If your using today's primers most shops use a high build-up product that will change the factory look, fill in details and make the edges, seams and details "soft" and not crisp like originally seen. IMHO