I did a little more digging on the FelPro's. The 1037 is listed in Jeg's catalog as "suitable for marine applications" and says it has a pre-flattened steel wire ring around the cylinder for better sealing. It does not say if this ring is stainless steel, but that might not matter around the cylinder bore. If I am getting water into this area, I have bigger problems. :eek:

The 17042 is listed as a MLS gasket, and Jegs' says it is stainless steel, contrary to what FelPro's tech support guy told me. However, it doesn't say anything about using them for a marine application.

I also found a third option - Summit lists a Q17042 as a Performance Marine Head Gasket. It doesn't say anything different than the regular 17042, doesn't mention stainless steel construction or anything special that makes it applicable for a marine engine. Hmmm - marketing gimmick to charge an extra $10 per gasket? :confused:

Maybe this will help, http://www.federalmogul.com/en/After...ermatorqueMLS/ or this http://www.eraceware.com/manufacture...7/index-2.html I don't believe a 170 any thing would be an MLS, I could be wrong.

So I was researching head gaskets and found this thread. The 811546A04 Mercury head gasket is what I was looking at. It is cometic right? I look at the ones on my Heads and see Black blow by in between the cyl. Is there a way to cure that w the new stock head gasket or is it going to come back? Any help would be great

I'd definitely make sure the deck is flat, and the heads are flat. I am not familiar with the mercury head gasket. If your heads and block are not finished with a suitable RA surface for a MLS gasket, I'd use the fel pro 17048. Also, I am almost positive, the Felpro 1047, is the same gasket, just in a different box and a little cheaper price. Both stainless steel core.

i have a phone number to a guy that makes the mercury gadket but better to his spec not mercurys..i dont like to use the fel-pro on the iron head bare,,i have seen a few leak over time...did you notice how the merc ones were stuck to everything lol well that has good sealing properties..they blow between the cylinders because thats the nature of the beaste,,simese blocks have no water between the cylinders so that spot will get hot..a good set of head bolts or studs would be best to use..factory ones most likely stretched causing a leak..

I've never seen issues with felpros between the bore even on 4.625 stuff and not much left that big. Cosmetics on the other hand I've seen problems between the bore even there wonderful stainless steel rot away. Not saying your a liar or trying to start anything. I think your posts are on the money and can't say that about alot of posters just saying I've seen different than you.

I'm thinkin' all that goo keeps the water out. But i see a little compression being leaked between the cyl. How much? Probably not too noticeble in performance. Or is it a big deal ?


Why are they using a 4.570 gasket on a 4.447 bore. Because it's a "universal size" or because the head combustion chamber size??:confused:

I will say this. this motor got a little hot. and I am glad that I am fixing this motor. It was blowing some steam when I got it. Meaning. The water pickup was getting air with the water.. My guess.. Somone rebuilt this motor ( top end only) and ran it ( because of this ) . it smoked a bit too. ( from getting hot I bet) I fixxed the water issue after i drove it once. Now it will be fresh and tight . I can't wait. Both motors will have fresh cam, lifters and springs too :D

By the look of your pic. Whoever did the top end didnt know what the hell they are doing or they do and just did crap work. The valves look like they are sunk in the heads... U should size the head gasket to the bore and the chamber to the gasket.

Thank You .. I thought that head looke like chit! So Now, I'm getting a set of heads from Young Performance ,plus a new block. That should make things right. Thanks again. PS that motor alway ran like chit! ;)