Need Some Engine Help

[thunderbolt]

That swap gets you to a 406. (not counting overbore) I am not sure if the pickup 390 was the same as the truck 390 (sometimes called the 391) but the latter has a slightly different size front bearing on the crank. (think this is right, front snout or something here, truck versions were larger than car versions and can be turned down to fit) If you find a 391 it can be bored to 428 specs and fitted with the crank. Not sure if you can bore it again.
Are the heads for the 390 different than the 428? I don't remember, seems to me like they were the same. I know you are not supposed to swap big valve versions onto 352's.
As you can tell I am no expert on FE engines but hope this gives you some help. That book "Ford High Proformance" has a large section on FE engines.