It breaks my heart to say it but Ruiz is probably the more skilled of the 2. However if Frank can land one good right hand Ruiz will go, and go hard.
I actually think Bruno would have confidence with this one. He builds a big lead and most likely tires late but Ruiz won't put him out like Spoon, Bonecrusher, Tyson or Lewis did. If Bruno hurts Ruiz I think he'll find a way to finish him. But I'll go Bruno holding on with a UD 12 with Ruiz coming on late.
I think Bruno was the better fighter however Ruiz's style of wrestling will exhaust Big Frank for a late stoppage.
The only concern i have is Brunos stamina. Otherwise id pick him to outbox Ruiz and maybe take him out. Probably early. Ruiz was nothing special. I mean neither was Frank, but he was still better than Ruiz
Despite almost everyone holding a piece, I don't really see Ruiz becoming a belt holder in the 80's or 90's. Which belt holder lets him get away with all that hugging?
Ruiz was the most successful, worst belt holder of all time. I think the guys of 80s would outbox Ruiz. Inconsistent or not, Ruiz brought little to the table.
I'd favour Ruiz to win on points. Ruiz had a good chin and while Bruno hit very hard I don't think he'll be able to land regularly enough or clean enough to force a stoppage. If Ruiz is able to fight in his normal clinching, spoiling style I think he can basically shut Bruno down. Bruno will have success with the jab but he was slow and would struggle to get off with anything first with Ruiz clinching at every opportunity. So Ruiz win's in ugly fashion on points.