4.3 lx to chevy 350 swap

[Shea_G]

My 4.3 lx has **** the bucket so ive decided to put in a automotive chevy 350. I have a backyard mechanic doing the job but hasn't done this before so I want to help him out with letting him know what needs to be done. The boat is a 1997 regal 2100 lsr. I know I need to: Get a marine v8 alternator brass frost plugs new marine v8 exhaust manifolds new prop (going to reprop instead of rehearsal) Move motor mounts forward Will everything else swap over from the 4.3? Am I missing anything? Dont know too much about marine stuff so any direction would be greatly appreciated.

 

[Bt Doctur]

the starter and alt ,brackets, wiring etc should swap over . If not pm me for a v8 harness. depending on the year of the motor the cam might have to be changed out.
brass core plugs in the block and heads.flywheel might swap out, if not hit the junkyards for a GM 350 clutch flywheel.triangular coupler might fit both motors.

 

[thumpar]

The motor mounts will probably be the biggest challenge. What did the motor come out of? If it was a truck the cam should be very close to a boat cam and work just fine. A lot of the externals driven off the engine will most times transfer from a 4.3l to a small block.

 

[Bondo]

My 4.3 lx has **** the bucket so ive decided to put in a automotive chevy 350. I have a backyard mechanic doing the job but hasn't done this before so I want to help him out with letting him know what needs to be done. The boat is a 1997 regal 2100 lsr. I know I need to: Get a marine v8 alternator brass frost plugs new marine v8 exhaust manifolds new prop (going to reprop instead of rehearsal) Move motor mounts forward Will everything else swap over from the 4.3? Am I missing anything? Dont know too much about marine stuff so any direction would be greatly appreciated.

Ayuh,... Welcome Aboard,.... It depends on the vintage of the 4.3l, 'n the vintage of the 350,.... The 4.3l is probably a '96, or '97, What's the 350,..?? The alternator, 'n the rest of the front bracketry oughta swap ok,...

 

[NHGuy]

Intake manifold, stainless head gaskets, ignition wires, dist cap & v8 rotor/ tone wheel. Is there room in front of the current v6 for 2 more cylinders?
While things are apart it's a very good time to clean up the bilge, reattach any loose wires etc.

 

[Shea_G]

The engine is a vortec 350 out of a suburban. Not sure on year but its going to be around mid 90s. There is room in engine bay.

 

[Bondo]

The engine is a vortec 350 out of a suburban. Not sure on year but its going to be around mid 90s. There is room in engine bay.

Ayuh,.... Vortec is '96, 'n newer,.....

You'll need a standard shift cast iron flywheel for the 350, the one on the 4.3l is different,...

 

[Shea_G]

The flywheel is on the engine already, can I just use that one? And how important is it to replace the head gaskets with SS ones?

 

[Howard Sterndrive]

flywheel on a Suburban? I've never seen a standard transmission in a late model Suburban. Flywheels are only on standard trans fitted engines. Auto trans vehicles use a flexplate attached to the torque converter, therefore no flywheel.