I have a set of M/T 33x10.5x15 that I got to try from a Heritage A/FD, he didn't like that they don't grow, which is what he was looking for. He tried tire pressures from 6# to 8#, and didn't like the way they handled. I know some racers want to try a narrower tire because they are not making 700-850 HP, and GoodYear is not making a 11" tire now, so on paper it looks like the 10.5 would be worth trying. In a way it's too bad the 10.5 tires are not made for FED's. I was interested in trying them after seeing how much Matt Hadford from Total Seal Rings improved his B/DA [ before he went to Pro Stock] when he replaced his 33x14.5x15 GoodYear and Hoosiers. Matt picked up about 2 tenths with the M/T on 14" wide wheels. After talking to slick manufactures and some racers that pointed out all the 10.5 tires are designed for the 10.5 door car classes. So I think the biggest difference in those tires is a lot stiffer sidewalls to handle 3000+ lb door cars and softer compound to work with "dead-hook, shift, dead-hook, shift," etc. Most FED's are looking for more tire speed to keep from pulling the motor down out of it's HP range.
I never ran the 10.5's because I was advised that to make them work, I would have to run a 14" wide rim, not legal for Heritage JrFuel. Also they weigh 44 lbs, a whole bunch more than the 22.6 lb D2585 GoodYear 31x12x15 we run now. You know it takes power to turn rotating weight. A common idea is one pound of rotating weight is equal to 9-10 lbs of static weight. so if your car is over weight now, and your car weighs less than 3000 lbs, you might be better off trying the GoodYear 31x12x15. We started out running the GY 31x12x15 slicks on 10" wide wheels, and as we made more power we had to go to wider rims, 1'st 11" now 12". The wider rims also helped with 1/2 track traction, but the with the wider the rims the tires grow less, ie higher trap RPM and/ or lower top speed.
There are allot of Heritage and ANRA NE-1 [ 7.60 bracket] FED's running GY 31x12x15 on 10" rims.
Jon, Hayden Wheels, 800-624-3803