Holley 1850 fuel transfer tube seals??
I did this 2 days ago when I put my Holley back on and changed the jets while I was there.
They are a tight fit for sure. I used a smear of clean engine oil and the tube pushed in just fine.
I had the tube seated in the rear bowl and then seated the seal in the front bowl and carefully slid it in, making sure it didn't try to push the seal in and distort it.