I have a 1968 ss396 with a rusted frame. What year frames will work on this?

68 - 72 chevelle, lamans, skylark and cutlass

Yes 68-72 will interchange, However for the purist the 68 frame is a one year only frame. Notice under the front crossmember you will see a plate welded onto it. This is 68 only. The 69 frame again is a one year only. The front crossmember design changed in that the crossmember and skid is one piece.The rest of the frame back is the same as 68. Now in 70 it changed again being the front crossmember stayed the same as 69 but the rear as it goes over the axel has a totally different design from the previous years. there are other smaller differences with the 70-72 frames from previous years.
Will a 70 frame bolt up to your body ? YES it just comes down to how correct you want to be. Frame from a Cutlass,skylark of the same year will work as stated, these i find have some additional mounting holes that differ from the chevy, however minor.
What state are you in? I have a 68 frame in Mass. that is mint

Good luck
John

Hmmmm,
I have a 68 SS 396 with a rusty body....lol