I think your saying that you have the nut off,but the bolt is stuck in the motor,right?If so put a blunt brass punch on the the bolt and tap it out with a hammer.
The degree key advances your timing,the offsets is what sets it apart from the stock one.It is a good mod to add a few extra horses,but I wouldn't go more then 3 or 4 degrees over unless all you do is drag race.
Get your flywheel lightened,head shaved,and your shift star modded (Boonman does a great job).
I also think the HQ price for a Noss head is $215.00 shipped,but check it out with Dave.
The only thing that I think that would be different between 18-10-8 and 18-10-10 is that the 10" would be a stiffer ride.I think the 8"er's would help soak up some of the landings.
just my $.02
I have to get some new fronts,and was looking for some info.The track I race on is a TT track that is clay on the out side,and hard pack on the in side.I was looking at the Hoosier 57" D12 compound.