Thanks guys
I will contact them. At the moment my 518 is a stock box with a non lock up 2800 stall converter.
A guy was telling me last night that because i am getting up in the HP range my 518s 1st gear will be too low with my 3.5 diff gears. He said I may be better to just run a 727 box and drop the diff gears down to 2.5 or 2.9
