I am posting this request on a number of Ford sites. Excuse it if you have seen it before.
Subject: Marine Engine Recommendations For 300 CI Ford Straight Six
I am new here. You are a very knowledgeable bunch and I am a complete novice, so I am going to ask the groupâ€™s suggestions as to what I should do to a 300 cubic inch straight six Ford that will be used to power a 34 foot wooden Jonesport (Maine) lobster boat ( I havenâ€™t a clue as to the weight). Engine is mounted up front, under a cuddy cabin. This is a work boat, not a racer, and what I am trying to do is get the cruise speed up from around 12 knots to around 16 knots (maximum speed is not important).
To do this, I need to maximize the Torque/HP in the 2500-3500 RPM range, and I donâ€™t much care what happens at slower and faster RPMâ€™s, nor do I need to have a red-line much beyond 4500 RPM. In this 2500-3500 RPM range, I would like to get as close to 250 HP as possible (with as flat Torque/HP curves as possible), consistent, however, with the following requirements for the engine:
(1). Operate very comfortably on 89 octane.
(2). Single 2 or 4 bbl marine carb (no multiple carbs and no fuel injection).
(3). Nothing radical (no excessive compression ratio, turbos, maximum over-bores, stroker kits, radical head-work, etc.).
(4). Simple and absolutely reliable (I will be going off-shore).
(5). Long engine life (no high-stressed components).
(6). Easy starting and smooth running (no radical cams), with good throttle response.
(7). Quiet (see single pipe dry exhaust system/muffler requirements below).
(8). Reasonable gas consumption.
(9.) Reasonable costs.
(10). The use of as many FMCO and after-market suppliers â€œoff the shelf, bolt-onâ€ components as possible (a minimum of special fabrications and â€œcobblingâ€ together of parts). Only premium quality parts will be used
(11). All components must be â€œcomfortableâ€ in a marine environment.
(12). The engine does NOT need to comply with any pollution control/emission requirements.
As to the exhaust system, I will have to use a standard marine, cast iron, water-cooled exhaust manifold (no truck exhaust manifold or headers are possible), but after this manifold, the exhaust system will be a â€œDry Systemâ€ (much like a truck), with a regular (single, not dual) exhaust pipe running vertically upward from the manifold into a regular type truck muffler, and then a regular (again single, not dual) exhaust pipe running vertically upward from the muffler out through the cuddy cabin top. For aesthetic reasons, I would like to use as large a diameter exhaust pipe as possible, and as quiet, and large, a muffler as possible. Total exhaust run, including muffler, will be approx. 12 feet, with a maximum of one 45 degree, and two 90 degree, bends. Carb heat can be supplied with this system.
As to the cooling system, the engine will be â€œkeel cooledâ€, that is, a closed loop, fresh water-anti freeze mixture cooling system, where heat removal takes place in a â€œkeel-coolerâ€ (sea water to coolant heat exchanger) mounted on the outside of the hull, below the water line.
Marine transmission is likely to be a Borg Warner Velvet Drive, with whatever reduction is appropriate (my guess now is 1.5-2.0 to one).
Prop will be sized (diameter and pitch) to take advantage, to the maximum extent possible, of the engineâ€™s output at the cruising RPMâ€™s of 2500-3500.
I would very much appreciate the groupâ€™s suggestions on the following:
(1). What â€œcoreâ€ truck engine (with part and casting numbers, if possible) should I purchase to start with (the original 300 Ford blew up and is long since gone). Is it possible and desirable to buy and use a new short or long block, given the block and head machining work that will be required, or is the â€œbone yardâ€ and a complete rebuild or remanufacture the only way to go economically?
(2). Block work (including machining, balancing and blue-printing, pistons, crank, rods, oil pump and other internal components).
(3). Which head (again, with part and casting numbers if possible) should I use, and what head work should be done (porting, polishing, valves, valve job, valve seals, etc.).
(4). Compression ratio, and how best to obtain it.
(5). Cam, lifters, rockers, push rods, etc..
(6). Induction system (type of manifold, 2 or 4 bbl carb and CFM size, heat or no heat, choke type, etc.).
(7). Ignition system (HEI or ??, vacuum or mechanical, wires, plugs etc.).
(8). Exhaust pipe diameter and muffler.
(9). Brand of high-output water pump (the keel cooled system only needs one water pump, same as a regular truck engine water pump), and the use of a serpentine belt to minimize parasitic losses.
(10). Gaskets, seals, etc.
(12). Whatever else I forgot to ask about specifically.
In making these recommendations, as much specifics (including suppliers and manufacturers names) and explanations as possible will be greatly appreciated. Remember, I am a beginner!
What does the group think the final Torque/HP numbers/curves will be in the engineâ€™s operating range (especially in the 2500-3500 RPM range)?
Finally, can anyone recommend a competent machine shop here on Long Island, NY to do the engine work AND, are there any books that I should be reading?
Thanks in advance for your serious thoughts on these requests, and your help and time! I am sorry to have taken up so much bandwidth, but I am trying to ask my questions all at once, and with as much specificity as possible.
Tom Barr (Sag Harbor, Long Island, NY).
Phone: 631 725 7447