will say in okla a gas 421 a 6 over with 13 paddle ext hooked hard, came up a bit, so an 8 would be ideal.
alky 421 thats been worked over a lot with a 12 over 25in 14 paddles ext didnt hook as hard as it should, never came up.
so 10 over with same tires would be probably ideal but each places is different.
take it for whatever you want but 10 paddles isnt enough with a 10 over i dont care what sandtoys says. if you want it to hook up trust me.
i run 10 paddles 21s with a 4 over for dicking around and they dont hook up good enough.