Are there any really major differences between 352 heads and 390 heads? Can I put 352 heads on a 390?

 

According to this, some were the same heads. Probably most. Do you have casting numbers off the 352 heads? Remember, they will not have hardened seats, unless they've been fiddled with.

FE Cylinder Head I.D. and Application Chart

 

Thanks! I was wondering because I was thinking of converting a 352 to a 390 and didn't know if i needed different heads.

 

As long as your block is safe at .050 over--sometimes a question--and you get the crank, rods and the right pistons, you are good.

What else are you going to do?

Note there are several pistons available, some with 8ish compression, some in the 9s and some 10+, so you need to watch out for what you want. Most low end rebuild "kits" give you the low compression jobs.