The recommended safe overbore for a 390FE is .030 (30 thousandths). You mat be able to bore it considerably farther if it passes a sonic check for wall thickness. Most well-equipped auto machine shops can do that or tell you where you can have it done. It's not what I would call prohibitively expensive.
std bore is 4.050
no you cannot bore it to 340 but you can put a stroker crank in it and get to 390, 396 and even more
390 kms
390 Light Years
about 390 miles
About 390 miles
.030
if I'm not mistaken, they are all like that(390's). The motor is the same as a 352, just a larger bore and longer stroke.
390 miles
It is about 390 miles.
the 352 ci is a fe motor along with the 390 but far as the same no the 390 is a bigger motor more power but will interchange with the 352 list of fe motors ,330 332 352 360 390 406 427 428
It is 390 miles accoording to Google Maps.