a 470 cid to a 3.0? your looking to go down to 140 hp in the 3.0 from what, 300+ in your 470? can you say, underpowered? if i may ask, what kind/size boat is this 470 in?
a 470 cid to a 3.0? your looking to go down to 140 hp in the 3.0 from what, 300+ in your 470? can you say, underpowered? if i may ask, what kind/size boat is this 470 in?
Currently looking at a 1979 grady white marlin 20 foot with cuddy cabin. It's what i'm looking for in a fishing/crabbing boat. The owner claims the 470 is in good working order. But we all know how that goes... I like bondos idea about dropping in a 4.3 if the need arises
Don't expect that to be an easy drop in either. Chances are you won't find a Y pipe for the 4.3 that will fit correctly on the transom shield, then there is the motor mounts on the V6 are on the side, not front mounted like the 4.3. You will also need a full Merc setup 4.3, including flywheel cover, coupler,, manifolds, ignition, wiring , fuel system, etc.
My 470 was a good engine. The only thing I did was the cam shaft speedi and changed to electronic ignition. I loved the meaty side of the 470, it was just time for a bigger boat.
I would agree with Bond-o and if you are going to do this, go with the 4.3.
What makes you think the 470 will "crap out" any faster than the 3.0? Do a compression test before you buy it. If OK you should be good for years. Make sure the cam seals are not leaking. IMHO going down to a 3.0 would be unwise and with the trouble and expense of putting a 4.3 into a 20+ year old boat would be a losing proposition.
