replacing a 5.0 with a 4.3

[Maxum21]

hello, i'm looking at '99 boat with a bad 5.0 merc engine for a very reasonable price. i've also found a nice running and cheap '93 4.3 merc complete. would this work out as far as motor mounts and compatibility with the new 5.0 outdrive?
thanks

 

[Don S]

Re: replacing a 5.0 with a 4.3

Going to a 4.3 will be a poor choice in my experience.
The 5.0L engines were used to "Just get buy" in most boats, as a cheaper sub for a 5.7.
A 4.3 would be a slug in those cases.

 

[Bondo]

Re: replacing a 5.0 with a 4.3

Ayuh,... It would probably be cheaper,+ easier to step up to a 350, rather than stepping back to a 4.3l...
350s are plentiful,+ cheap,... All of the stuff off the 305 will fit on the 350...

 

[TilliamWe]

Re: replacing a 5.0 with a 4.3

hello, i'm looking at '99 boat with a bad 5.0 merc engine for a very reasonable price. i've also found a nice running and cheap '93 4.3 merc complete. would this work out as far as motor mounts and compatibility with the new 5.0 outdrive?
thanks

As said above, 4.3 in place of a 5.0 is a step backwards.

Front motor mounts would need to be moved back approx 4.4 inches in the boat, to account for the missing cylinders in the middle of the block of the 4.3.

The gear ratio for the 5.0 would work okay for the 4.3, but you may need a really low pitched prop.

But really, find a nice running 5.7 (1996 or newer, though) complete and you'll be much better off.

 

[Maxum21]

Re: replacing a 5.0 with a 4.3

yea i think im going to keep looking. the 4.3 prob would have been enough power since its only a 19.5' open bow boat, but its simply too much of a gamble...buying a used engine i cant "test drive" iprob would be a poor idea anyway .. thanks

 

[mylesm260]

Re: replacing a 5.0 with a 4.3

Here's a thought.

a vortec 4.3 will make more HP than a non-vortec 5.0

my vortec 4.3 open bow 21' boat does 61 mph (gps)



seeing as how the motor you were looking at was a 93 however, I wouldn't bother.

IF, you could get a VORTEC 4.3, with a GOOD set of manifolds, then I would say go for the 4.3.

However, in you're case, I would get a low milage vortec 5700 out of a chev 1500, and marineize that with you're parts.