Hi Conrad, The converter issue has been talked over quite a bit. Higher stall converters slip more under their stall speeds. This generates excess heat. I'm not sure what the stall speed is on the # 7? I think it's 2,800rpm's?
I've talked with guys that have the 3,500 stalls and they say in over-drive it will heat up the fluid real fast. Installing an extra Tranny cooler can make a world of difference on that.
On the other hand, The higher stalls really put the power to the wheel.
If I were to get one for my 1 speed, I would have a Coan ground up built to these specs. Stall speed in the 2,500-2,700 rpm range with the lowest possible multiplier. For the 2 Speed I'd go with a lower stall so you can use the overdrive. 2,300-2,500 and an extra cooler or two.
I've read that a high multiplier will put more power to the wheel at the start (great for burnout's) but still slips in the higher rpm range.
The lower multiplier does the opposite. Less initial power and a more positive lockup in the higher Rpm's.
That's about all I know and this has just been my opinion. I'm sure that others may know more and I hope they add to this.