Does anyone know if someone makes chrome stainless round style risers that bolt to stock mercruiser manifolds?

also , for a stock 7.4l 330 hp engine , whats the best bang for buck for 25-35 more ponies?

thanks in advance

Yes hardin marine and I think Imco make some .CP Performance carry hardin. 272 FORMULA FOR SALE

Camshaft change.

I have used the Imco stainless riser on the stock manifolds but you will not gain much.
For bolt on upgrades: Replace your intake with one of these.
http://www.holley.com/8017.asp
and change the entire exhaust with a good flowing alum manifolds and rises like Stainless Marine.

how long would an aluminum intake last in a raw water cooled application , or is there slip in bronze jacketing that can be used ?
anyone ever used the aluminum manifolds/risers from GLM?
they look cost effective and supposedly have the indevidual runners that help your power production

No bronze insert in that manifold. An aluminum intake will last for a few years untreated. You can have in hardcoat anodized for added protection.
The GLMs are a decent product but you will not gain much power. The least expensive good flowing manifolds are Revolution Marine.

I have aluminum Merlins in my Formula. I don't know how long they were on the boat before I bought it, but I've had it four years, and I just recently pulled the t stat housing to check for corrosion inside. Not a sign of it. Flush 'em reall good, and they will last a long time. For people who say aluminum won't last in salt water, what do you think your drive is made from?

As always OSO community is the best