Can I change exhaust manifolds to different style?

[Terestron]

I bought a 1987 boat with twin 4.3L V6 Crusaders. It sat for 10 years and the exhaust manifolds on one engine split open due to freezing water. However for the life of me I can not find replacement manifolds. It is a GM 262cu in engine and I can get other brands of exhaust manifolds such as mercruiser that will bolt on. would that be ok? I know that I would have to adapt the exhaust to fit going to muffler. but just wanted to check if that is what most people do?

BTW the Crusader parts numbers I need are 97484 and 97485.

Both engines have been removed and stripped down and going through the rebuild process.

 

[Lou C]

Yes you can but you will have work with a local shop if you have that available to you to try different elbows (for example, Mercruiser sells elbows of a few different angles to mate up with the Y pipes on different installations). You can also use Volvo Penta exhaust but Merc has the advantage of the better designed dry joint system and I believe they have more of a variety of angles for the down slope of the exhaust elbow...

What you could do if you still have your old units is bring them in to a marine exhaust shop and try to match up either a Merc or Volvo system that will put the outlet of the elbow in the same position as the O E exhaust....the height...angle...and reach of the elbow...has to be close to right....to get all the parts to line up...depending on your installation...

I had to do something similar with my old '88 OMC 4.3, converting the one piece manifolds that have been nla for years to the later style 2 piece exhaust used by both OMC post '90 and Volvo Penta from '94 on up. Because VP used the same set up as OMC the parts needed were still available (exhaust pipes that adapt from the 4" elbow opening to the 3.5" Y pipe and the hoses/clamps for these...the manifolds and elbows I was able to use standard Barr replacements for Volvo/OMC. Cost a bit more due to the extra parts needed but that's a one time expense only. Because Volvo adopted OMC's general design when they were in the joint venture with OMC and produced the SX drive, these parts were easy to find because they were used on V/P 4.3s from '94 all the way up to when they converted to the cat converter exhaust....

 

[Scott Danforth]

Not sure the merc dry joint is that much better

In addition to aftermarket volvo or mercruiser, you may want to look into hitek marine as well