A Few Things To Note 
1) The numbers on the sides of the cars originally started out in the KB 5 packs where numbers 1 thru 9 was available.
2) Only one numbered car to date, the #3 car (a pink 70 Dodge Challenger T/A), does not have a diecast blown engine.
3) Tom Lowe (former owner of Playing Mantis) did the development work on the engines and the #5 engine was too big, so he let the factory chop off the right side valve cover.
4) Not all numbered cars are available in one KB 5-pack, you'll have to buy several. They come with an assortment of other cars.
5) Not every engine fits every car, so some cars won't get some engines.
6) If you were to ignore the #5 listed point above, and counted the total possibilites of each release, with each car having different engines and wheels, these would be the totals:
Rebel Rods release 1 - 48 total different combinations. The Silverado and 7 engines hampers the total for this release.
Rebel Rods release 2 - 68 total different combinations.
Rebel Rods release 3 - 68 total different combinations.
Rebel Rods release 4 - 68 total different combinations.
7) Rebel Rods started on #11 and currently will end at #19 while going back and filling in the much anticipated #10.
8) Playing Mantis did not number or name these engines (nor did I) the way they are listed on this site. It was a collaboration of fine folks from Playing Mantis' bulletin board. They can be found at this Hobby Talk location.
9) New card art was implemented for the 4th release showing a '69 Super Bee. Previous releases showed the '69 Nova (Boss-a-Nova). See the card art car pics below.
10) According to PM, release 4 was considered a flop. Retailers didn't want them so the remainder of release 4 was sent back to the factory to be re-packed. The re-issue of Rebel Rods release 4 is now called Spoilers under the Street Freaks program.
11) Rebel Rods release 4 is now showing up at Cracker Barrel stores and has been re-packaged in a window box form. These are not labeled as Rebel Rods (or anything else) but simply as "The Collectors Choice". (added 8/7/2004).

Card art for releases 1-3 

Card art for release 4