Welding '03 frame to '37 Buick frame

I read somewhere that modern car frames cannot be welded directly because they are heat treated.
I'm looking at installing a front suspension from a '03 donor car on 'my '37 Buick.
The front suspension bolts onto the '03 frame.
1) Instead of fabricating the bolt pads from scratch, could I cut '03 chassis frame in front and back of the bolt points and then graft those sections to my '37 Buick frame? I would not remove any of the existing Buick structure, just add grafted section and then box everything. This would probably save a lot of fab time.
Thanks

In a word YES..........I'm trying to get the exact answer.(waiting for my tech to call back) You have to watch that you don't exceed the temperature determined by the manufacture. You use a paint stick that melts at that temp and don't get it hotter than that. You have to weld then let it cool then weld and let it cool....let it cool no blowing air no water. it has to cool by it self. It is stronger if you do half laps not cut off then but weld.

Nascar guys do there frames with plates welded at right angles to the frame tubes at a few different places--then with crash damage they cut off at the plate and butt weld the next section right to the plate---first time I saw it( down at Rick Hendricks) I thought yuk, but after thinking about it for a while it makes perfect sense--of course the structure of the cages reinforce the frame rails---

I found the reference.
The book "Hot Rod Builders & Chassis Builders Guide" says "some modern high performance frames are made of high tensile steel that does not respond well to being cut or welded." I would not expect that a 03/04 Crown Vic would have a chassis made of this high tensile steel.
1) Can anyone confirm this is the case?
Thanks

I was told you can mig weld it but should be fish plated. To much heat makes it brittle.

cffisher
Thanks for the info.