Which one ?
 

CMI etop or stainless marine
Motor merc stock 502mpi



Final destion !!!

Stainless marine

Sm

lightning
 

;-)

Bigger gains in one or the other?

The Stainless Marines will last longer. Since its a stock 502 the difference wouldn't be noticeable. On a performance motor the true tube header would shine more.

Sm

After conversations with Eric @ Teague and CP Performance I went with CMI eTops over SM and Dana.

I've read alot and haven't heard where ss headers make more power than sm. if this is untrue please advise. Also what would the difference be. After reading these forums I have 0 faith in ss headers.

Only thing I hear all the time about CMI headers is that they leak and get engines ruined, never heard of a SM manifold ruining an engine. They could leak externally after 15 years or more if not properly flushed, but their design would not allow internal leaks that cause engine damage. Just my .02

I used the Dana cast aluminum manifolds and made over 1700 HP. They worked very well and there's nothing to leak.

CMI headers that were of the original spec for Mercury are the issue.

CMI makes better headers, but that's not what Mercury spec'd for OEM. THAT is the "CMI issue". CMI gets the bad wrap, but it's all Mercury's fault.

I don't fully blame CMI. I've read of a bunch of manufacturers headers who leak. It's inevitable. When they do, bye bye motor. I'd take less bling for better reliability.

I know any exhaust can fail at anytime. It just seems headers fail frequently.

Get the Stainless Marine GEN III setup.

X2 CMI's are a bad design and make less power.

eric at teague
 

Is a good guy, but they only sell cmi and imco.