I think 1500-2000 is way too much if you want your best leave. I don't think your combo matters at all. Everybody has their own ideas on this. But if you have a slant 6, a mountain motor or something in between, pick your shift point, lets say that is 6500. Get a converter that "stalls" (when I say stalls I mean the first number you see on the tach when you leave the starting line) 1000 rpm's below that. This should put you near your torque peak like some people want. Some people put their launch rpm 1000 below stall speed, but lower may work better. I like to leave at the lowest rpm I can. Sorry for the long answer I guess I just should have said 1,000 rpms.