Can siamesed bores go to sea

Question

Some petrol engines have siamesed bores which can cause overheating problems on land. The gen 1 cast iron small block 400 cid chevy motor is a well known example. Often engine rebuilders prefer making 383 cid with 350 non siamesed bore and 400 crank. Sure the 383 has a good reputation unlike the controversial 400. My question is would siamesed bores be good for marine where lots of cold water is available.

Answer 1

There is no reason why siamesed bores cannot go to sea (or lake or stream or waterway). Would they be good for such applications? That's subjective. It doesn't matter if you are on the water or on the street, the siamesed bores are going to provide you with the same issues and/or benefits. The big benefit to running a 400 over a 350 or 305 (or even 383) is more cubic inches which equates to more torque. And torque is what you need in boats.

From your question, it appears you may have a few misconceptions or old ideas. A 383 no longer is done by stuffing a 400 crank into a 350 block. There are tons of kits available to do this without the throwing a bunch of mismatched parts together to make something work. The 400 crank had different sized main journals, which meant you needed specialized bearings in a 350 block to use it. The cranks in the kits have the right main journal size in the so you can just throw them in there with some minor clearancing in the block (which you'd have to do the old way too). It's pretty slick.

If you were going to go the route of putting a 400 into a boat, you'd be better off getting an aftermarket block, or going the LS route.

In marine applications, they use a heat exchanger. The engine has its own cooling system using antifreeze and anti-corrosion properties. This coolant runs through the heat exchanger, then outside water from what you're boating in flows through the other side of it, which cools it. This is done for two reasons. First, if you ran raw water through the engine, you'd have huge corrosion problems. Second, you stand less chance of introducing contaminates into the body of water thus polluting it.