G-48  Obsession

Page 9 - Getting ready for Clayton & Wolfeboro !!!


Owner/Driver - Bill John

1946 Gar Wood, hull number 7115, modified

Speedster design, single aft cockpit, 21 foot

Bottom modified to a shingled/stepped hydroplane

Honduras mahogany hull with Spanish cedar steps

Chevrolet 510 cubic inch marine stroker motor, 630 HP

Prop is a Menkens high rake 3-blade, 13x17 cupped

Tacked at 75 mph on GPS at the 2004 Detroit Gold Cup

Obsession video - let it load & crank it up!!!

In June of 2010, after years of hard running on the Vintage Race Boat Circuit and the constant use here on beautiful Lake Winnipesaukee, our beloved Obsession was hauled back to the shop for some TLC. The hull remains in excellent shape after our Edge-Bonding project over eight years ago. The edge-bonded seams still look fresh, but more importantly added great strength to the hull. We are now busy in the shop on a refresh and getting ready to run again on the vintage circuit. Work has begun on additional bottom detailing, complete drive train refresh, a new Menkens high rake speed prop and of course, lots of fresh Epifanes varnish.




On the last rebuild of the motor, the plan was to build a new Chevrolet 502/502 marine crate motor, but then Leo at R&L Engines recommended another option. We talked a lot about the time honored method of getting more power from a motor, to overbore the cylinders and increase the stroke of the crankshaft. The result is called a stroker motor, and Leo convinced me to use my seasoned Crusader 454 marine block and build a 510 cubic inch stroker motor. R&L Engines built a batch of them and they all dynode between 625 and 650 HP. Stoker motors also produce lots of torque, right in the midrange, perfect for a gentleman's vintage race boat. So we spent a lot of time and money into good machine work. We over-bored the cylinders .o6o inches, balanced the stoker crankshaft 4.375 inch and breathed more horsepower into the Brodix aluminum cylinder heads and tuned the ports of the matching Brodix aluminum intake manifold. We also used the best components, including a custom roller cam with roller rocker arms,  and a complete MSD marine ignition system. This  reverse rotation marine motor has a low 9.5 compression ratio and runs on 93 octane fuel through the modified Holley 830cfm carburetor. A marine bell housing connects the modified Borg Warner direct drive transmission. The current speed prop is a Menkens 13 x 17 with a super cup and lots of rake that lifts the bow at speed. The rev limiter is set at 5,400 rpm's to preserve the motor and to get another season before the next rebuild. This motor is a bullet and the sound through the IMCO exhaust headers and the 4 inch side pipes is pure magic. Obsession was tracked at 75 mph on GPS at the 2004 Detroit APBA Gold Cup.

Obsession video - let it load & crank it up!!!



The fun continues - the summer of 2011 !!!

We picked up Obsession from winter storage in June of 2011 and hauled to the shop to prep for the Wolfeboro 4th of July Parade and the trek to Valleyfield, Quebec. Then back in the shop for some touchup before our boat show.


Continue to - Obsession Page 10


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