1979 Impala Oldsmobile Engine Swap

Hi all,
      New to forum here. I just purchased a 1979 2 door coupe, Impala with a knocking 350. I have a Mondello built 455 thats currently in my 81 Firebird that I would like to pull, along with trans, and put into the Impala. Anyone ever done this? Seems straightforward but not positive. Also, if you've done this, what headers would I use? I used Cutlass headers for the pontiac and it worked well.

Use what u used on firebirds depending on the year fire bird the fron frames and engine bays are damn near identical.

I put a Buick 455 in my 77 Caprice years ago and there was no room left for headers. Ends of the control arm bolts were in the way. I had to cut them back a bit as it was. Not sure exactly how the Olds motor compares in size dimension. You may have a little difficulty with the motor mounts. I had to set my motor in, get it level and where I wanted it, then tack the frame pads, pull the motor back out and then weld the frame pads in. It wasn't hard but it wasn't a straight bolt-in either. I had a universal bellhousing TH350 trans so locating the motor was as simple as bolting it to the tranny and getting it level.

I think the gent with the e-mail at the bottom of this link could be very helpful; I used to belong to this list but left when I sold my last Olds. My memory is that the physical dimensions of the big/small block Olds are very similar save for the deck height but I can't recall if you use the engine mounts that came with the engine to be transplanted or the mounts that fit the body. If you want to construct your own rear cross member with double humps for true duals, get another c-member from another b-body, cut it in two shy of the trans mount and turn it around so you've got the humped section under the driver's side once you've welded it up. When you look at the second c-member, you'll see what I mean. You may need to "deflect" the floor pan slightly but you won't be paying for an expensive alternative. I'm thinking the Olds List members liked "Honest Charlie" headers for fit? 'Not sure but that's why the other group might be helpful. Good Luck!
http://oldslist.oldsgmail.com/

Thanks for the replys! I appreciate your thoughts and time! Heck, maybe I should simply do a decent 350 build,.. I don't know. I hate these kinds of decisions. Gotta say, finally found one and I love them.

You could put the focus on finding the 455 a new home and look for one of the big Delta 88 two door coups from 70-72 to put it into, a swap I'd always admired. If you put the Modello engine in a Chevy, that's OK too. People who have no knowledge of, or affection for, Olds engines have been happily pulling them out of Oldsmobile and sticking plain Jane Chevrolet 350s in their place for decades, Chip Foose being one of 'em (and he took a lot of flack for it too, LOL!). I also appreciate it costs more to build an Olds instead of a Chevy but you've got that 455 whispering in your ear. Keep us posted on developments, please!

You could put the focus on finding the 455 a new home and look for one of the big Delta 88 two door coups from 70-72 to put it into, a swap I'd always admired. If you put the Modello engine in a Chevy, that's OK too. People who have no knowledge of, or affection for, Olds engines have been happily pulling them out of Oldsmobile and sticking plain Jane Chevrolet 350s in their place for decades, Chip Foose being one of 'em (and he took a lot of flack for it too, LOL!). I also appreciate it costs more to build an Olds instead of a Chevy but you've got that 455 whispering in your ear.  Keep us posted on developments, please!