Bit of a different setup, but replaced the stock merc anchors and risers with Stainless Marine exhaust and risers on my stock 454 mags. Everything bolted right up and I am very pleased with performance gain.

Not sure of MPH gain as went from pilot (old VDO) to GPS speedo.............did Imco nosecones at the same time. Would guess I picked up 4 - 5 MPH between the 2 upgrades.

Had to move up to Mirage 25's from 23's to keep the R's down and now 73 MPH on a good day.

I stand corrected you are absolutely right. However, as my hull at the stern is now higher out of the water, so are my drives. The whole "schabang" is nearly two inches higher now. If the hull "came up", the drives, as they are attached to the hull, came up with the hull. (did that make sense????)
But you are indeed right, the "X" stayed the same.

What dya expect, I just be a dumb carpenter....

My EMI's worked fine but they are close. I got the 3" extended SS risers. One side clears fine but the other side barely touches the mirrorplex under the hatch on one riser. Made a small dimple in the mirrorplex but no one sees it but me (my wife says I'm anal - imagine that! ) If my boat doesn't sell I'm going your route next year Outlaw. Extreme Marine platform and some SS tips.

Friend of mine put stainless marine in his 311, I believe he put a 3 in spacer in that he bought directly from stainless marine.

Looks real good...

Funny, I have a small "dimple" on the port "outside" of my hatch cover too.

Yup, me too. I have the EMI stainless risers.

I would also look at Stainless Marine. They make nice stuff. I'm thinking I may go that way next time, and someone else mentioned here using them. However, it is nice that the spacer is built into the riser with EMI. Did not know that it is separate with Stainless Marine. Less parts = less chance for leaks.

Isn't THAT the truth....

I went with the Stainless Marine tips with the internal "SuperFlapper" and it does NOT make any "flapper noise" which I've heard on many other tips with internal flappers. Too Old turned me on to these and could not be happier.

Jay, did Gordon have to weld water passages shut in your risers??

I have water jackets in my risers. When I had my 3 inch spacers made up I took a riser as a template. When we went to install (the manifolds were already on with duct tape over the openings to keep moisture out) guess what, no water jackets in the manifolds. After straddling the fence on what do do for about two weeks and asking everybody (yeah, I know, you're all just wincing here) I finally said screw it and bolted the whole thing up. My spacers do get warmer than the risers but not HOT. If it ever got hot enough for steam to form, the steam would follow the easiest way out, up the waterjackets, and out through the risers, etc. I actually probably do get some cooling from the water that does get in there.

All in all I don't think it should be a problem.

He did weld those shut. There was no need for them, and they were leaking from the previous owner's install. Now EMI only sells them w/o water passages, most likely due to all the leaks their customers have experienced.

Are you going to loose your Merc HP robbers ? If yours are original I'd get rid of them now before they let go and grenade a motor...not worth it, or did you replace those already?