tire question - 50 merc

I have a 50 merc I’m trying to shoe with some nice fat white walls. i ordered a set of Goodyear super cushion 710/15 which have a 4 inch white wall when i got them they accidentally sent a 670/15 super cushion deluxe (with only a 2 3/4 white wall so I sent them back) but i was shocked at how skinny they looked. I'm putting them on probably a 6-7 inch rim. the tread seems pathetically skinny I can't imagine the 710s having that much more tread unless they balloon a lot. so I think it will look dumb if i put those on. I also plan on slamming it so I’m concerned that a 28.5 inch tire is just too big. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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So my question is what’s a good tire size combo for the merc, I want a big gangster white wall but I want it to not look like it’s on ballerina shoes. Am I underestimating the 710/15 once its inflated and on the rim?<o></o>
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denman G78-15's for me.

 

Read this thread:

http://www.jalopyjournal.com/forum/showthread.php?t=208333&highlight=tire+bias+merc

This is helping me find my new tires for my pile o'junk.

 

I was gonna say the same thing.

 

G78-15 is the equivalent of 8.50-15, I seem to remember.