Replacement Engine

[Lucky Penny]

I know this question has come up before, but I just can't seem to find the answer. At present I have a 1977 Mercruiser (small block Chevy) 350 CID 250 HP and considering replacing it with a newer engine. The casting number indicates a 1978 small truck/marine/other applications.
Question: what are the differences between a Light Truck Engine and Marine Engine (other then the T-Stat housing. and exhaust manifolds.

Thanks

 

[zbnutcase]

Re: Replacement Engine

Head gaskets, cam profile, core plugs, M-400 bearings(the GOOD ones) and thats about it.

 

[indy440]

Re: Replacement Engine

waterpump

 

[chriscraft31]

Re: Replacement Engine

Tey are basically the same. A truck engine will work just fine in fresh water if you exchange the core plugs with brass ones and put your alternator, starter, intake manifold, exhaust manifold etc on it.

 

[Lucky Penny]

Re: Replacement Engine

what is was looking to do was get a long block and replace the starter, alternator, exhaust manifolds from the outgoing engine. what is the difference between the cam's on a light truck engine and marine engine? I also know I have to transfer the carb and fuel pump.

 

[chriscraft31]

Re: Replacement Engine

The cam is just an rv type cam to give you more power. I have put one together with a stock automobile cam and it runs great. If you are going to order a long block, have them put in an RV1 cam and have them install brass core plugs and you will be good to go.

 

[Lucky Penny]

Re: Replacement Engine

the primary reason I am looking at a light truck engine over a replacement Mecruiser block is cost. roughly $800-$1000 Other than the core plugs and head gaskets everything except the marine specific add-on's (alt, fuel pump, starter and carb) are the same.

 

[chriscraft31]

Re: Replacement Engine

You got it. One other thing I forgot to mention, there should be a baffle that bolts on the main bearing cap, or one built in to your oil pan that helps keep the oil from rushing to one end of the pan when you are rolling in a boat.

 

[Bondo]

Re: Replacement Engine

Other than the core plugs and head gaskets everything except the marine specific add-on's (alt, fuel pump, starter and carb) are the same.

Ayuh,.... Yer Gittin' it.....

You'll also gonna run into Vintage Issues....
In 1979, the Dipstick switched sides of the block,....
(pan mounted dipstick might help)
In 1987, the crankshaft,+ it's bolt pattern changed,....
(flywheels Won't interchange)
And, in course, in 1996, the Vortec heads were intro'ed...
(Vortecs are Way Better heads)

More to think 'bout,.....

 

[Cptkid570]

Re: Replacement Engine

Where are you looking for long blocks and what type of prices are you finding? I bought my longblock from Rapido and it really wasn't much more expensive than the truck long blocks at the auto parts stores.