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08-07-2010, 10:24 PM
I just recently got an old fiberglass 16' "runabout" powered by a Ford 351-C V8 engine with Holly 4-bbl, and a Hamilton jet outdrive, circa 70's vintage. I would guess roughly 250 HP.

Q: How much of a "gas hog" is this thing apt to be? (gph) Do I need to add "lead substitute" additive to the fuel, or is unleaded ok? The previous owner said it would do 47 knots max. Is that realistic?


Nick Olzenak
08-12-2010, 01:42 PM

That is going to be a good bit of horsepower for a 16 footer. Speed will truly depend on the weight of the hull however 47 knots with 250HP on a 16 foot runabout would not be uncommon. The factors will be condition of the engine and the hull weight. The Ford 351 C should be just fine on regular unleaded fuel. If any engine modifications have been made over the years raising the compression you may get smoother operation by running a higher octane fuel however it would most likely not be required.

Any boat regardless of the era is a good boat. :)

Good luck!

Steve Herschbach
08-12-2010, 04:55 PM
HI Marshall,

Yeah, it will be a gas hog. That is one high performance motor and one reason they stopped making motors like that was fuel economy issues. Fuel consumption will depend on throttle setting but I'd not be surprised to see 15-20 gph.

08-12-2010, 10:01 PM
Thanks Nick and Steve. That's what I was afraid of, but 15 to 20 gph comes as a bit of a shock....I was thinking maybe 5 to 7 gph. Hmmm...maybe that's the reason the previous owner had it parked in a corner of his back yard for years and years...he'd take his little aluminum skiff w/outboard out instead...

Steve Herschbach
08-13-2010, 07:23 AM
Hi Marshall,

I am afraid in have overstated the gph based on the same motor pushing a far heavier boat. It will burn some serious fuel if engaged in full throttle river running but your 5-7 gph figure may be far closer to the mark for your particular boat under normal use. So don't despair, fire it up and find out!