Cracked block

"hey guys,
I have a 84 Ebbtid

"hey guys,
I have a 84 Ebbtide Catalina XL and its got a 5.7 liter chevy 350 with an OMC outdrive. The block apparently had a hairline crack when I bought it that wasn't detectable by me or the dealer i bought it from (or maybe they swindled me). It finally dumped its oil 3 weeks ago, lost power and I couldn't start it and keep it running. Anyway, everything else on the motor appears fine. My question. My brother has a car 350 that he built and isn't being used. Also, I can probably get a block easily around here. Could I get a block from a car and swap all the parts over or is there really that much of a difference between a car block and a marine engine? I know very little about motors, but I have a friend who is very skilled about building car motors and he could help me with this mega task."

I repowered my Sea Ray 240 wit

I repowered my Sea Ray 240 with a crate motor from GM. Works great.
There are a few things that you need to change. One is the freeze plugs and the other is
the camshaft. You want it power and tork ranges to fall between 0 and 5000 rpms.

"ditto - what Janoman said - i

"ditto - what Janoman said - if you swap EVERYTHING and just use the long block from the car you're good to go - the cam is important, get a marine cam (better) or reuse the boat cam. You might want to use the timing cover and damper from the boat engine too - because on some car engines, where the timing marks are, you can't see them with a timing light strobe once the marine water pump is on.....GM was weird with timing marks - all over the place on various applications.
Oh, one other thing - Chev crankshafts changed around 1987/88. Make sure the car engine is the same side of that date line as your boat engine or the drive coupler won't bolt up."

"Chev cranks changed to the 1-

"Chev cranks changed to the 1-piece seal design in 87 model year. If the engine is stock - check the cam duration and lift on the auto engine compared to boat engine. GM used same cams on many of their auto/marine/industrial engines for a few years in the early 80's

if looking for more power an RV/Marine cam can be purchased from any speed shop. Blocks and heads are same between stock car/boat for early 80's vintage. Depending on what your brother has done, you may or may not have any performance increase.

If you rebuild yourself, a good GM crate motor would work, or put one together with a new short block, vortec heads, RV/Marine cam for about $1000"

"Hey I just went through this

"Hey I just went through this long block exchange ($1,900) and it ended up costing me more than the purchase of a replacement with a new Vortec engine. Mine was a 1988 and during the exchange of components from my block to new block, I discovered starter was rusted and shorted out, oil pan had rust dimples, water pump was wobbly, fuel pump was fouled, just to name a few things. When I added up labor, new parts and delays, I ended up spending well over another $1400 above the long block price. In my case, I should have considered the age of engine and condition of other parts before I went the long block route. I am smarter now. But I am down for an oil leak that I can't find but I suspect is from the valve cover. This is not fun anymore. Haven't used the boat at all this year. Good news is I'm saving on gas bills and it is sometimes very relaxing just sitting at the dock as stereo works fine and adult beverages are always cold. Have Fun and Good Luck."