[CJ428CJ]

If you want inexpensive and you want an FE, then go with a 390. They're still easy to find and as a result are inexpensive. $150 to $300 for an original bore rebuildable motor is probably about right. If you want more power and something a bit more authentic, go with a 428. Although from outward appearances you can't tell them apart from a 390 they are more desirable and they command a greater price. Still, you should be able to find a rebuildable motor for about $1000. Unless you have lots of money to spend, stay away from the 427's. They always command a premium price if you can find one at all.

You mentioned 429s and 460s too. Neither of these are part of the FE family.