I'm looking at an '03 SS37, and noted blisters around the perimeter of the dome lights on the undersurface of the radar arch. Not bad, but they are there. Salesman says the arch is aluminum and the stainless screws fixing the light bezels are causing corrosion. What? First of all, what are these arches made of, aluminum or fiberglass? Is his explanation legit? Sounds strange to me. Any thoughts?

If the arch is aluminum and the screws are stainless, then he is correct. It could be corroding due to galvanic action caused by the disimilar metals. The stainless will be fine, the aluminum will go south. However, for that kind of galvanic corrosion to occur, water is needed. Why there would be enough water in the arch area to brew up this corrosion is odd. Is this a salt water boat? That would explain a lot.

The plot thickens.....This boat has been in a marina, in brackish water, not on a lift. This particular marina was used in WW II as a construction site for Higgins landing craft, to ferry the troops from the ships onto the Normandy beachs. So tell, during the 'hurry up, we need this for the war', effort, that scrap aluminum, was merely thrown into the water. Which is now a pleasure boat marina. (Read) potential electolosis.
I spoke to a marine mechanic in Baton Rouge who said he currently has a boat from that marina with electrolosis damage to the outdrives.
The sales dude said the boat was pulled out of the water a month ago for a survey required by a bank, for another interested party, and that there was no pitting or electrolosis damage to the drives. Uh, huh. I dunno. I sense whispers of smoke here, and where there's smoke....
I'll get my own survery out of the water if it gets down to 'pen in hand' time. And get the B.R. mechanic to get involved too. Caveat emporer.

I dont know what you are paying for it, but a guy I know here in AZ has a 04 370SS with low hours on a trailer and currently garage kept. It has the 496 HOs and he is right around $150k for the price. He just put $5k into the stereo also. I have seen the boat, it is clean and the trailer is brand new. I have a 370SS also, 2005.

What is cruise and top end w/496HO's?

You may also see cracking at the base of the arch. This is where they use bondo at the factory to make the aluminum conform to the fiberglass. My 02 400SS has this same problem. Do a chin up in the arch while looking at the affected areas. If you can't see it separate or flex with your weigth on it then it is fine. It's probably just cosmetic.

Well....are there any pics and what options on the AZ boat? Hours, colors, what does NOT work, or need attention on the boat and/or trailer?

Trailer is brand new, he just bought the boat this year and built the trailer for it immediately after he bought it. He keeps it in the garage. I dont think anything is wrong with it. he fixed all the minor stuff when he got it. He called me about 10 times asking questions about what does what and he fixed every little thing based on the calls he was making to me. Boat look clean and he has had it in fresh water only (Arizona lakes).

The guy stepped on my boat and then decided to get one of his own. Like me, he was coming from a high performance boat. He doesn't like the speed, it is too slow for what he wanted. You'll see 53-54 MPH WOT. It seems to match the RPMs at cruising speed. So 3500 RPM gives you between 35-37 MPH. 4000 RPM is around 40-41 MPH. I tend to cruise around 3800, and run just about 38-39 MPH.

Here is the boat trader link. Give him a call, his name is Billy. He put a very similar system to mine in, put some TVs in the arch as well. Has 2 10" subs under the seat behind the driver, and some custom panels on the arch for 6.5" speakers. He even bought the same truck that I have to pull it with.
http://www.boattrader.com/listing/20...LA-SS-92824126

Best I have seen is 54 MPH with the HOs. I normally have a full load of fuel and gear on board. I cruise around 3800 RPMs and it runs about 38. RPMs seem to match speed. 4000 RPMs runs around 40-41 MPH.