Guys, I just read through this whole thread and I didn't see any mention of the kickdown switch...is there one and is it working properly? I know this won't make any difference on initial tire spinning torque but it still makes a big difference on the overall 0-40mph performance.

I to have a '69 400/400 and I've fully ported the heads and have had the original carb fully rebuilt and dialed in professionally but my car still doesn't have tire spinning power. Through numerous conversations with the list the only thing I have left to check is the torque converter. I'm not sure what's in mine but I'm eventually going to get a new one with a bit of stall conversion.