What's the difference between V8s, Chevy and Mercruiser

[Valv]

It's still me trying to find some answers on I/O systems.<br />What is the difference (if any) betweer a Chevy 350 V8 engine and a Mercruiser 350 V8 engine.<br />I assume they should be almost the same except for cooling system, pumps. <br />I am just trying to figure out why Mercruiser motors cost more than twice a Chevy motor.

 

[kev_79]

Re: What's the difference between V8s, Chevy and Mercruiser

Mercruiser is an older chevy in a boat. Key word, in a boat. Luxuary item, pleasure toy, what ever you wanna call them, but if it is on a boat, on the water, it is more expensive. Just look at the fuel prices on the water. That gas isn't for cars, it is for a boat, hence 1 gallon cost about a kidney. <br />On boats, you will find many things like this. That is why we are all here, to learn, and to mend our own, but some things you will have to just turn around and drop you pants, because there is no cheap way out.<br />

 

[Valv]

Re: What's the difference between V8s, Chevy and Mercruiser

Kev, I learned that many times. Recently I had to replace the main shaft for a Crysler 120hp, retail of it new was $ 525.00 !!!!!!!!! Found it used at $ 125.00.<br />That thing is a 2' long steel with splines at the end....that's it..I was in tech school, when young, and we used to build them during lessons...no way they can justify $ 525. Even in a shop they can make it new for 1/2 of that price.<br /><br />My question is based on the fact that I have a old '78 pickup in the yard, motor runs perfect, tranny and body bad......A rebuild will cost me $ 650 and I'll have a new 350. Now, the outdrive will be the banger... k: <br /><br />Thank you for your input.<br /><br />Val

 

[kev_79]

Re: What's the difference between V8s, Chevy and Mercruiser

well, I am not sure that you could swap, the late 70 chevy would coincide with a late 80's early 90's mercruiser. I think that you can depending on the model of the boat. If your mercruiser has the bolts on the valve covers that don't go down the center, rather are around the edges, and the intake bolts go in at an angle, rather than straight down, then I am most certain it can be done. Mercruiser changed this, I think, in the late 80's early 90's. Take a good look at the engines for these types of similarities, and other than possible mounting bracket headaches, it should work. Let me know what you find and good luck.

 

[Rex]

Re: What's the difference between V8s, Chevy and Mercruiser

BASICALLY THEY ARE THE SAME.<br />BUT YOU ARE TALKING ABOUT A BIGGER CAM AND HIGHER COMMPRESSION ON THE ENGINE.<br />I WORK AT G.M. <br />PLEASE TELL ME IF I'M NOT RIGHT.<br />IF SO I'M SORRY.<br />REX

 

[kev_79]

Re: What's the difference between V8s, Chevy and Mercruiser

Rex, what do you mean about bigger cam, or higher compression? In which engine? Last I checked, both compression ratio's were about 9:1 on both engines. Actually 9.4:1 for sure on the mercruiser.

 

[Rex]

Re: What's the difference between V8s, Chevy and Mercruiser

kev_79 read what you wrote and it the same<br />as what I said except about the cam and the<br />water pump and exhust.

 

[Walter]

Re: What's the difference between V8s, Chevy and Mercruiser

Valv...<br /><br />One key difference in a marine Chev 350 is the gasket kit. Oil leakage in a boat is NOT a good thing...therefore marine grade gaskets provide better protection against leakage...<br /><br />Also, the electrical components (alternator, starter, etc) are of a sealed type and cost many extra dollars than an automotive type...<br /><br />Walt

 

[fone_man]

Re: What's the difference between V8s, Chevy and Mercruiser

Walt... is right about gaskets, oil & fumes of any type are dangerous when in a confined space as these are mechanically removed via blowers. Carb/Gaskets are different also because of fuel vapors. Freeze plugs are different as Cam which is designed for sustained RPMs depending on engine. So dropping a normally aspirated auto/truck engine without doing the modifications required for marine application would/could result in explosion or dangerous situation for occupants of boat.<br /><br />But basics of engine block are the same but to be in compliance with USCG; replacing the existing components with approved would be your first step before lowering into your boat... search this site as we have had various discussions in June & July in regards to this topic.<br /><br /> ... BOOM!

 

[MercilessMike]

Re: What's the difference between V8s, Chevy and Mercruiser

Gasket sets, FREEZE PLUGS and oil galley plugs are of different material. Mounting hardware is also stainless.

 

[Valv]

Re: What's the difference between V8s, Chevy and Mercruiser

Thank you guys, I agree on modifications before installing it. My goal is to have Chevy 350 rebuilt with marine gaskets, then, since the don't come with manifolds, pumps alternators etc. replace them with Mercruiser or marine type. It is only a matter of cost, since a rebuilt Mercruiser (block only) will cost me $ 2750. A rebuilt Chevy $ 850. With the difference I can afford all modifications, which they need to be added anyway on a rebuilt Mercruiser.<br /><br />Thank you again for your help, this forum is really, really a lifesaver (USCG approved.. )<br /><br />Val

 

[clanton]

Re: What's the difference between V8s, Chevy and Mercruiser

If you are using the 1978 chev engine. I dont think the heads had the steel valve seats for unleaded fuel. Anyone know when the changes were made?

 

[fone_man]

Re: What's the difference between V8s, Chevy and Mercruiser

I would imagine if "Valv" was going to do re-build on 350 he would have heads reworked before install... but this is only an assumption... What are you going to do "Valv", keep us posted.<br /><br />Good point by the way "Clanton"!!!<br /><br />

 

[kev_79]

Re: What's the difference between V8s, Chevy and Mercruiser

The changes were made before 78, in 77 for sure. Don't forget to run a marine carb, or make mods to an automotive one, if you don't, rough water will make the engine run rough.

 

[Valv]

Re: What's the difference between V8s, Chevy and Mercruiser

Ok, Ok guys I found a great deal. On Ebay there was a motor from somebody here in MN. It is a 327 GM rebuilt then removed from houseboat. I got the whole unit for $ 300 !!!! Includes everything except exhaust manifolds. Carb, starter, alternator, motor mounts, etc. <br /><br />I need some help finding more details about it. If you want to follow link below, it'll take you to a newer topic.<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=17&t=004050 <br /><br />Me and my wife are so excited to have found a marine motor that runs (I cleaned carb, pump, sprayed WD40 into plug holes, connected lines, changed oil + filter...and...wroooomm..a little loud but it runs good, so far) and it was so cheap. Owner didn't know was a marine motor.<br /><br />Thanks.<br /><br />Val