F1 chassis in the 70's were made of aluminum, CF was used for the chassis starting with the 80's.
This is one of the best sites I know for F1 related detail photos:
http://www.gurneyflap.com/formule170%27s2.html
You'll find the P34 about 1/3 down the page.
However given that in the 70's most F1 cars were using the same Ford Cosworth engine you can surely take a look and get some inspiration from the other 70's Tyrell pictures you'll find on the site (I saw there are quite a few of them).