2020 small block race?

I am actually going to try and compare the penalty box against some of my Fords. To see if it is possible to cross over for say, Ford, Chevy and AMC. I have a stock 289, mild 289, better 302 and a mild 351w all in cars.
Based on using the 318 level for the 302 in a Mustang it would have to run a 12.2 and the 351 in a 68 Fairlane would have to run the same 12.2.
The mild 289 would have to run a 15.2 in a 65 Fairlane. The stock 289 in a 68 mustang would need to run a 15.9 if my math was right.
If we have some stock 383, 400, 440 ie tdc car with a 727 BB or manual BB #'s for baseline would be interesting to see if we could put together a chart.
I would like to see a chart for the slant guys.