Replacing a cracked block

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Apr 22, 2020
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Bought a boat (1998 vip vixen) 5.7 mercruiser. Took it out one night and oil was full of water. Pulled it apart, cracked block. Bought a motor off market place remaned and ready to go. Come to find out the one I had was carburetor and the new one is a vortec motor. No luck on exchanging . I am looking to convert this motor to carburetor. I know I will need to add an electric fuel pump and change the intake bit I am having trouble finding and exact part number/brand for a 5.7. Any help would be appreciated. Trying to stay fairly cheap if possible as ibe already bought a boat and motor and still can't enjoy it. Tia. also I'm new to the forum thing so whatever rules I'm breaking let me know.
 

Scott Danforth

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Bought a boat (1998 vip vixen) 5.7 mercruiser. Took it out one night and oil was full of water. Pulled it apart, cracked block. Bought a motor off market place remaned and ready to go. Come to find out the one I had was carburetor and the new one is a vortec motor. No luck on exchanging . I am looking to convert this motor to carburetor. I know I will need to add an electric fuel pump and change the intake bit I am having trouble finding and exact part number/brand for a 5.7. Any help would be appreciated. Trying to stay fairly cheap if possible as ibe already bought a boat and motor and still can't enjoy it. Tia. also I'm new to the forum thing so whatever rules I'm breaking let me know.

my guess a mod moved this out of your 10 year old thread

96 and later motors are vortec. what makes them "vortec" is the cylinder heads primarily and the roller cam

has nothing do do with the induction. vortec motors came in carbed, EFI (also called TBI) and MPI (Multi-Port Injection)

is your motor MPI? if so, why are you looking to convert to a carb?

as for exact brand of your General Motors 5.7 liter base engine. its a GM motor built out of the same parts bins as a TRUCK in the Tonawanda engine plant. other than brass core plugs, a MLS stainless head gasket and a marine cam, there is no difference on the long block.

as the long block gets dressed up, the circuilating pump and all accessories are marine.specific

Help us help you.

what is the serial number of your current busticated motor and what do you have that you bought off of face-tube market place that you were planning on using

Cheap and boating are a dichotomy
 

Bondo

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I know I will need to add an electric fuel pump and change the intake bit I am having trouble finding and exact part number/brand for a 5.7.

Ayuh,..... Welcome Aboard,..... I started a thread, All yer own,.....

If you ever go into saltwater, you want a cast iron intake, or a bronze lined aluminum,......

Fuel pumps for carbs need to be limited to 'bout 6/ 7 psi,.......

How it's wired up, makes it marine,....
 

nola mike

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'98 *should* be vortec anyway, but depends on your engine. Also should be electric fuel pump. Also, Scott Danforth , thought they went to roller cams in the 80's?
 

Scott Danforth

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'98 *should* be vortec anyway, but depends on your engine. Also should be electric fuel pump. Also, Scott Danforth , thought they went to roller cams in the 80's?

Corvette went roller first in 86 for the 1987 model year
F-bodies went roller in 88 mid year for the 1988 model year
Trucks were hit-n-miss in the 91-95 range
boats and trucks went roller cams in 1995 for the 1996 model year when the Vortec heads were bolted on.
 

nola mike

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Jeez these engines are confusing. Scott Danforth wrote:

"the reason is that GM used roller cams from early on in the automotive market and the industrial engines (including marine) got the roller cams later when the vortec heads came out. Just like the SBC for 1988 was first year for roller cams in cars, trucks came in 89, however the boats didnt come until 1996. however to boost hp, the 1992-1995 marine 4.3 also got the roller cams that the truck motors got."

So did the 4.3's get the earlier rollers, but the v8s didn't? I could have sworn that my '89 4.3 had roller cam.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jeez these engines are confusing. Scott Danforth wrote:

"the reason is that GM used roller cams from early on in the automotive market and the industrial engines (including marine) got the roller cams later when the vortec heads came out. Just like the SBC for 1988 was first year for roller cams in cars, trucks came in 89, however the boats didnt come until 1996. however to boost hp, the 1992-1995 marine 4.3 also got the roller cams that the truck motors got."

So did the 4.3's get the earlier rollers, but the v8s didn't? I could have sworn that my '89 4.3 had roller cam.

Mike, 4.3's were sooner to roller cams, those hit in 1988. Trucks with V8's were hit-n-miss depending on which chassis and engine plant in the 91-95 time frame. not to mention my memory may be off a year or two.

point is, not until 1996 did boats with a 1996 model year motor get a guaranteed roller cam 5.7 V8
 

nola mike

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Gotcha. Guess I assumed that the V8's would have changed over at the same time as the V6. More confusion.
 
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