How to make sure 4.3 or 3.8 V6 ?

[MarkoL]

I bought this summer Four Winns Horizon 180 from 1998 and previous owner was 100% sure that the engine is 3.8 L V6. I did some research and found out that this engine must have been replaced. In the middle on 80`s 4.3V6 came out to replace the 3.8 V6. So it must be old rebulilt engine. I can´t find any ID plate or anything which proves that this is 3.8. I found some info that tells it is GM engine but nothing more. The engine replacement is done in Finland by unknown workshop, and now the boat is in Estonia.
Can anyone tell me how to make sure, what it is and what are the performance specs of the engine?

Thanks

 

[Scott Danforth]

welcome aboard

look at the side of the block at the casting numbers behind the starboard head (casting number of block) and on the side of the port side of the block (core number including displacement embossment)

however the boat being 1998 would have originally have had a 1996-2007 generation of 4.3 that is 6 generations of V6 newer than the 3.8
that motor would be vortec heads (8 bolt intake) with center bolts on the valve cover, balance shaft, serpentine belt, 168 tooth flywheel with a 1-piece RMS

a 3.8 would take a bunch of parts to get it to fit as the 3.8 would be non-vortec heads (12 bolt intake) with perimeter bolts on the valve cover, non balance shaft, V-belts, 153 tooth flywheel with 2-piece RMS and if mounted in the solid mounts of the post 1993 4.3 would vibrate like a dog passing a peach pit.

until you know what you have, performance specs would be a guess. however the 3.8 was 155hp and below....where the 4.3 was 175-225hp

 

[MarkoL]

Some pictures may help

https://1drv.ms/u/s!AnLuo8a30zwIgTAkZ3Gfd2hwTafx?e=IjOASI

I need to take a look of the engine block but valve covers are like 3.8, V-belt and what is the one-piece RMS or two-piece RMS?

 

[Scott Danforth]

I dont click on links to look at pics. feel free to follow the photos tutorial in the rules and guidelines forum.

RMS is Rear Main Seal.

the 3.8 is also about an inch narrower than the 4.3, so the exhaust wont line up straight with the y-pipe.