Is that right 8 1/2 inch tires i would say at least a three shoe clutch what i would do is contact one of the clutch manufactures tech people see what they suggest. Post some pics i wana see those tires.
You could always upgrade to a 1/8th clutch, I'm trying to remember a few good places to get em. Racers-Edge , Tekno RC
Or you could upgrade to an Aluminum 3-shoe clutch as mentioned above by w bill. Integy makes a decent one, I am using it in my Revo with an OS .21 and it has held up good so far. I recommend you upgrading your clutchbell, Robinson Racing makes good quality products.
that integy clutch set WILL NOT hold up to those tires. the clutch shoes will melt under that kind of load on them
you will need to upgrade to a 1/8 scale 3 shoe clutch
you will need to mod the chassis to move the trans forward ,so the CB and spur will line up correctly
I agree on the Integy clutch. I ran one with stock tires, only because thats what the shop had one day when i needed one. It did a good job with the stock tires but when i put some larger ones on it ate itself up real quick. Save your money and goto a 1/8 scale like mentioned above.