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Can i swap a chevy zz4 engine from a truck over to my boat to replace the 5.7 litre 350 mercruiser?

S

sbh6159

New member
Hey guys i posted on here this spring about a possible cracked block but luckily it was just a bad head gasket... my questions is this i have a chevy zz4 350 sitting in my shop thats out of an off road vehicle i used to have and was wondering if it is possible to swap this engine with the engine in my boat and if this is possible what all modifications have to be made if any. I figured if i have a better engine just lying around why not use it as an upgrade in my boat if it is possible. Thanks guys!
 
is it close in year wise to the boat motor.

ie: Both before 89 ?

If yes you will need the mani's the starter, and alt off the old motor. If they are both carbed even better.

Give a little more info on both motors.
 
Like Chief asked, What year is your boat?

As long as the bellhousing bolt pattern is the same and the crank shaft flywheel mounting is the same (if not you will need a new flywheel and coupler to match the ZZ4) then all you need is a set of marine head gaskets, brass core plugs, marine starter, swapp all your other parts. If you currently have log style exhaust manifolds, get center risers (a must).

optional but a must for a more powerful motor, better ignition (stand alone electronic distributor with external coil) A 650cfm -750cfm marine carb. Also run what plugs reccommended for that motor.....Also you will need a much bigger flame arrestor to allow more air flow....

Thats all I can think of for now.........
 
I don't know anything about a Chevyzz4, but, if it has more horsepower than the 350 did and is a stern drive setup, look out! Those Alpha 1's were only able to handle up to 300 hp. Good luck, Bob
 
02603sec said:
interesting. If this is true I wanting that aluminum headed hydraulic roller forged rod 572 BB to replace my 502
Click to expand...
You can't run an engine with aluminum components in salt water unless it is closed cooling. You might also consider supercharging your 502 ( with air-to-water intercooling ). This will add another 30-40 percent more horsepower at about a third the cost of a new engine. There are lots of really good performance cast iron BBC heads too.
 
Just some background info for some of you about the history of the high torque issue with mercs...........

First was the TRS drive, This drive was a monster and could handle big power, but it was way to big and heavy for a smaller boat with high power. (pleasure boating) ( they had high power stuff but it was not available for the pleasure boat crowd due to cost)
In the mid '80's they started to install some 454's into smaller boats and were using the alpha 1 gen I But they were blowing the upper gear cases apart under hard acceleration when starting off. I believe in ~ 1989-1990 the came out with the Bravo 1 to resolve this problem. This drive was much lighter than the TRS and offered the high power in a smaller boat withot the "boat anchor" hanging off the back of the transom.

A 22 ft with a 454 and a Bravo 1 and a good stainless steel prop was now capable of 65 mph + with little or no effort and no concern of blowing the outdrive apart........
 
As far as swapping auto for marine long block I don't think the auto ca shaft will work very well. You will need a marine cam as well. Sounds like it might be a lot cheaper and heck of a lot simpler just to change a head gasket.
 
The cam in the zz4 is marine compatible. Drop it in and go for it. You may also need a new bell housing to clear the new style coupler if this is what you end up doing
 
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