View Full Version : GLM exhaust manifold & Imco SS risers

11-10-2011, 06:56 PM
Trying to put together a budget performance exhaust system with individual runners in manifold & SS risers. Does anyone have experience with GLM manifolds & Imco SS risers on a sbc in a Classic 18? I saw Rootsy sold a similiar setup in 2010 and wonder who has performance experience with this setup? I run in salt water and fresh water cool the engine but raw water cool exhaust manifolds & risers. Any systems for sale? Thoughts? Thanks, Bob

11-11-2011, 07:16 AM
Unless you dump $$$ in the engine there is little to no gain from exhaust, you will get a little weight lose. The weight thing is greatly exagerated, these classics need weight aft. The more you move back the better the boats run, they also require less trim. Aluminum does just fine in salt, I have had several clients and myself run aluminum. It actually lasts longer than iron given the same care. Phil Phil

11-11-2011, 02:21 PM
I have GLM in my 22C and Mercruiser SS risers. I ran this same setup in my Baja and my buddy runs the same in his Baja. The Mercruiser SS are the same for SBC and BBC. If you want a set, my bud has a couple. Place in Miami area has GLM's cheap(e-bay) and I got mine NEXT day for just over $300. SBC are cheaper. The GLM is a very nice manifold, better than OSCO or Barr in my opinion and as good if not better than OEM. I had mine over 5 years(sold the boat) and my bud ran his almost 10 in salt water. The risers last forever so buy a set. I think he wants $300/pr and I think they are NIB.

11-12-2011, 10:29 AM
I am still weighing pros & cons of cast iron vs. aluminum in the GLM manifold. If I can't find Imco SS risers I may come looking for Mercruiser stainless. Thanks, Bob

11-12-2011, 12:11 PM
I also run GLM 's and Merc's stainless risers for years. Didn't want to spend more on exhaust then i did on the motor. I think I made the right decision.

11-12-2011, 04:28 PM
I think there is still a set of Imco's up on Boat Freaks, look at the for sale section under Gil risers for sale. Phil