I have a connection like that and it leaks. The bolts that hold that knuckle together are spring loaded so in theory it would work...but it doesn't. I also have solid mounts.
"In Oldskool we trust"
I have a ball joint style header, no springs on flange, motor mounts, no flex joint, fully welded exhaust. No issues 3+ years later. Cant say it will work out like that for everyone
Ball flanges are designed to flex... but I put a flex pipe in anyway, regardless of the fact I had solid mounts a cheap header will crack if its put under any stress at all..
Buy a flex pipe... yes you need one, especially if you dont have solid mounts..
Buildin' n' Boostin for 08' - Alex Richards
i cracked my ron header (cyl 1 runner... one crack near the head, and one crack near the collector) because i did not place flex pipe after it, and i have poly mounts...
i repaired the header, and will install flex pipe on the next build... (i no longer daily drive the car)...
it took over a year of daily driving to crack it.