Actually Lenny, the mechanic, noticed it on reassembly.

did your motor(s) fail, or did you just decide to rebuild??

my buddy just redid both of his blower motors, and while testing he decided to have Nickerson look at his plugs for him under the microscope. Dean told him that there was water coming from somewhere on the one side of the motor. So we pulled the one side and didn't see anything obvious until we pressure tested them and found the crack. Who knows how long it's been cracked???

I'd been having problems with one I had rebuilt last year, and the other was just due.

Good luck Steve! Keep us posted.

After a few months of gong through a high-pressure welding process & testing, I rec'd the manifold back. Lenny tested them & says they're STILL junk!
UN-BELIEVABLE!!!

I found this ad in the PARTS section:

Condition: Used
Make/Model: Gil Offshore Al. Manifolds & Tail Pipes
Price US $: $ 4,500.00 OBO
Two Sets of Gil Offshore Aluminum manifolds for 454/502's with 4" SS Gill Tail Pipes.

Seems pretty high, doesn't it?

What exhaust have the OEM's changed to?

I have two sets of Gils from my old Spectre with HP500s.
Looking to sell with the 4" tailpipes for $2,500 for everything. All 4 manifolds and all 4 pipes.

Shawn

Send me an e-mail address and I can send pix

I replaced my '96 Merc/Gills last year with the same problem. Hairline cracks at the top of the dividers.

I was getting a lot of steam in my exhaust. When I replaced them I saw that a few of the exhaust valves were pitted pretty badly.

I replaced them with CMI unitops that I got from Jones Marine Inc. They beat Teagues price by a decent amount on a group purchase we did last year.

I must preface these comments by saying I am not a mechanic.

Mercury used gil for the first two or three years of the HP500. A very common complaint was leaks @ the manifold / riser area. They stoped using Gil and went to CMI. The current 500EFI's use CMI, which is a full header & tailpipe.

Stainless Marine, alum exhaust manifold & chromed pipes look great, work well and never leak. They have a very simple way for measuring their tailpipes, have a quick turnaround, give you exactly what you measured and the polished stainless always looks great.

CMI has a slightly more complicated way of measuring. Tailpipes take two to three weeks, have a slight adjustment you can make when installing but do not always align perfectly ( order set number two ). The CMI's, being a full header look very cool and their stainless also stays polished & pretty for a long time.

Have run hundreds of hours with both products and never had a problem.

enough typing.... I'm going boating. 75 degrees in MD....time to burn fossil fuel