You are correctThe indexes did vary widely.
Yep That's where I found it.“nhra super stock national index”
Classes start at A and it goes by the highest power to weight ratio. Factory listed shipping weight and factory rated horsepower. So SS/DA is the 4th class from the top. The A On the end is automatic. It would be SS/D for a manual. Bun1979 cuda and challenger with a hemi was in SS/D, the B bodies moved to a lower class, heavier car.
The sanctioning body can add horsepower to a combination if it goes to quick, so the class and car weight can change over time. To keep it fair. LOL
in 1967 the class index was not 10.20
Back in the day there were many suctioning bodies and they had their own rules and allowed combinations. The indexes did vary widely.
in 2021 the stock eliminator cars are faster than 1970 pro stock cars were at that time.
type in “nhra super stock national index” to see the current 2021 page. You can get an idea of the variety. My machine is faulty today and can’t post it.
A little off topic but your question been answered. Have you taken a wrench (1-1/8")to the harmonic balancer bolt and tried to turn the engine over? Looks like no spark tubes and maybe no spark plugs. Any pictures of your friend with or without the car. Take lots of pictures as you work on car. I wish there was digital cameras when I bought my car. Original owner let me take pictures of pictures when he owned it.
The pistons won't come out the bottom, up is the only way to go.I have not even tried.
My thoughts = Don't try to turn the engine over at all.
I know the engine has been sitting inside of a barn for well over 30 years with no sparkplugs and no intake. If there is rust in the cylinders, I don't want to scar up the walls any worse than they already are.
I'm going to be pulling the engine out this weekend and remove the heads.
If the cylinders look ok at that point I will try to turn it over.
If not I will remove the oil pan and remove the pistons from the bottom.
If you remove the crank, the pistons won't come out the bottom?The pistons won't come out the bottom, up is the only way to go.
A little off topic but your question been answered. Have you taken a wrench (1-1/8")to the harmonic balancer bolt and tried to turn the engine over? Looks like no spark tubes and maybe no spark plugs. Any pictures of your friend with or without the car. Take lots of pictures as you work on car. I wish there was digital cameras when I bought my car. Original owner let me take pictures of pictures when he owned it.