Two vendors make them, and they are just as the originals. J&E and CP are the only vendors and are made specifically for NHRA Stock Eliminator. Both are not crazy money and better quality than the current and old TRW pistons. The only TRW piston available now is the 12 1/2-1 and have the smaller ring lands, 1/16 and 1/8" oil ring, and you have to cut the dome. Cosmetically there are much different than originals.
The J&E and CP have the correct dome height and ring lands, 3/16" oil ring and 5/64" top and 2nd ring. They're not thousands of dollars either. Andrew from Hendrick Motorsports does all of our machine work along with Keith Dorton, brother of the late Randy Dorton. We've rebuilt and restored hundreds of 302s over the past 25 years and thanks to our sponsorship with HMS we have the best machinists on the planet doing our work. We are very thankful for that.
If you have questions, you can always email us. Be glad to help.
Jerry