I am wondering if you can actually test these somehow. I just got 2 sets from another member and 1 of the tails appears to have been leaking at a weld near the flange.

How can I test the rest?

go to home depot and but one of those sewer stoppers that you fill with air,,make sure its the longer one and shove it in the tail to cover the water ports and fill the stopper with air...take the other end where the hose goes on and your going to have to adapt it down so you can fill it with about 10 psi of air,,i use a piece of hose with a valve stem for a rim for you cars tires...then i fill the bath tub and set the tail pipe in the tub and look for air bubbles..

This is what I did to pressure test...

And we ended up having all 10 headers bad which lead to needing to rebuild all 5 engines. (Two 600s and three 700s) Going to start checking headers far more often to be sure water is not leaking back down into engines.

that works good for the headers,but i believe the op is talking about the tailpipes.

Whoops read too fast. Just saw CMI and pressure test and all our Problems caused by bad CMI headers immediately came to mind

So sad we all go through this. I just pulled my last header that I have not bought yet. Sent to CMI, waiting to see what they say. I lost both of my 525's and this past yr my 700's to leaking CMI headers. Just unreal I tell you. Even had to buy all new pipes, and I pull the drain plugs after I flush each time.

ya,i can unerstand that,the merc specked cmi,s have ruined many of otherwise good engines.

Where is it actually stated that the merc speced CMI headers are of a lesser grade/quality to getting them directly from CMI? I've heard lots of debate on this topic but never really seen much to back it up

How in the hell are they still in business . Some of these leaks look to be caused by very poor welding . Lack of penetration and lack of proper fusion or knitting technique . This is either rushed welding , lack of welding knowledge or no pride in craftsmanship . They certainly need a QA department as apparently they have none . Looks good to me mentality don't cut it . I studied on the welds on my used Sport Tubes and this set seems to have been welded up by someone that knew what they were doing . The stainless looks to be good quality and the inner tubes show no sign of erosion or fatigue . These are of 04 vintage and have never leaked . My conclusion is if you were lucky to get a set welded up by a craftsman and properly annealed i'll bet they don't leak .