Good timing! I have the Supercars Annual issue (published by CARS magazine) for 1969, 1971 and 1972. Have been checking eBay a few times per month for the 1970 edition.
One showed up on Monday with only one day left. One other bidder besides me; fortunately, I was not outbid.
Below are a few scans of the '70 issue. I am eager to read the test results of especially the SS 454 Chevelle, the Hemi-'Cuda, the 440-6 pack Charger, the Buick GS 455 and 429 Ford Cobra and Mercury Cyclone Spoiler.