4.3 engine swap year range

[kmarcom]

I was hoping you could lend a new boater some advice. I recently purchased a 1992 Sea Ray with a 4.3 mercruiser, alpha one gen two. The block is cracked but the boat appears in really good shape. I am looking to do an engine swap with a junk yard find. In all of the reading people always reference 96 and up engines. Being that I have a complete engine I am trying to find what issues I am going to run into if I purchase a ~2005 4.3 out of a Silverado 1500. I know that I will have to change the intake and carb, add a fuel pump and regulator, recommend brass plugs and head gaskets. How serious is the marine head gasket? The boat will only ever see fresh water. Will all of the engine accessories and exhaust manifolds from the 92 motor bolt onto the ~2005? I could find an older motor but with as old as those engines are getting it seems like the seals are either going to be dry rotted or 280K miles. The later models are much more appealing but there seems to be a gap in information, everyone wants to talk about the 90’s. Perhaps they know something I don’t? What other nickel and dime parts do you foresee adding to the total bill?
Thank you for any information you can offer.

 

[alldodge]

Getting a newer vortec motor will provide more power, but the accessories (power steering, alternator) may be the issue with mounting. GM has had changes thru the years and some mounting holes my not be there. Agree, intake and carb but there should be no regulator to change out on a carb motor.

Your not getting many comments because the thread was posted in the OB section. I have informed the Mods and they will move it to the Merc section

 

[jimmbo]

This might start a war, but a junkyard auto/truck engine is not going to have a camshaft profile that matches the needs of a boat.
Fuel pump needs to be USCG approved, same goes for Distributor, Starter, Alt, and Carb.

 

[Scott Danforth]

Here are some reading

https://forums.iboats.com/forum/eng...history-of-the-4-3-liter-with-casting-numbers

Carter marine fuel pump part number P4389

your current distributor from your '92 will work, so will the starter, alternator, valve covers, oil pan and water pump. you will need new brackets, damper and pulleys from a 1996 or later MARINE motor because the automotive ones will not work and your 1992 motor was most likely belt. you may be able to use your old brackets, however you will be using spacers with the pulleys.

if your 1992 is a balance shaft motor, you can use the flywheel, if not, if the silverado was a stick, the flywheel from the truck will work.

since the 4.3 comes from a silverado, the cam is fine.

need marine head gaskets and a marine vortec intake unless you put fresh water cooling heat exchanger on the motor

suggest new exhaust manifolds and elbows.

if your 1992 is a non-balance shaft motor, you need to replace the squishy mounts with the later balance shaft mounts.