4.3 Vortec Swap

[17mattc1998]

I’ve gotten a lot of great help off of this forum and wanted to share what I’ve been working on, a 4.3 MerCruiser to 4.3 be Vortec swap.
I finally got the timing right and it runs great.

 

[17mattc1998]

I’m trying to post on my phone and it doesn’t work the greatest. The picture I posted is of the original engine, it was cracked in the valley and the intake was also cracked. I ended up pulling a motor out of a 2002 Astro van.

 

[alldodge]

Good deal

 

[Scott Danforth]

I’m trying to post on my phone and it doesn’t work the greatest. The picture I posted is of the original engine, it was cracked in the valley and the intake was also cracked. I ended up pulling a motor out of a 2002 Astro van.

the pic of your original engine is a vortec (8 bolts on the intake)

you will be using the block and heads from the astro van. you will need to swap all the core plugs from steel to stainless or bronze (check first, some are stainless from the factory)

you will need marine head gaskets

you will need to swap over all the accessories, rotating electrics, intake, ignition, etc.

you will need a marine water pump

since you have freeze cracking, buy new exhaust manifolds vs trying to use the old ones.

I would switch to a 4 barrel carb at this point.

 

[nola mike]

There are some gotchas. I did this swap, tag me if you have any questions.

 

[Rick Stephens]

There are some gotchas. I did this swap, tag me if you have any questions.

I can't really think of any......

 

[nola mike]

I can't really think of any......

I can. Carb brackets, changing pulleys/removing reluctor ring under crank pulley, dipstick doesn't fit, some bolts are metric, starter may not fit, water pump may not fit, squishy v non squishy mounts... Although he's going from a serp setup on a vortec so I guess a lot of those don't apply.

 

[17mattc1998]

the pic of your original engine is a vortec (8 bolts on the intake)

you will be using the block and heads from the astro van. you will need to swap all the core plugs from steel to stainless or bronze (check first, some are stainless from the factory)

you will need marine head gaskets

you will need to swap over all the accessories, rotating electrics, intake, ignition, etc.

you will need a marine water pump

since you have freeze cracking, buy new exhaust manifolds vs trying to use the old ones.

I would switch to a 4 barrel carb at this point.

Well I did some of that I actually have it in the boat running now I bought it in the spring thinking I could get it done in time to get it on the water this summer but I couldn’t and now I just finished it up and got it running.
I ended up using the heads still on it and just replaced the intake with a new marine one. After that just swapped everything over as it was and got it running.

 

[Rick Stephens]

I can. Carb brackets, changing pulleys/removing reluctor ring under crank pulley, dipstick doesn't fit, some bolts are metric, starter may not fit, water pump may not fit, squishy v non squishy mounts... Although he's going from a serp setup on a vortec so I guess a lot of those don't apply.

All of those items just swap over from original motor.

 

[17mattc1998]

All of those items just swap over from original motor.

Yep everything swapped right over to the new motor I was able to use all the old accessories from the motor that was in the boat on the new motor. I just made sure the block casting numbers were the same

 

[nola mike]

All of those items just swap over from original motor.

If you're using the same vintage motor, yeah.