I am starting my next boat build, 19' mahogany runabout. a 265 cui engine was about the largest engine that was in the original design . I salvaged a 1:1 velvet drive ,drive shaft and 12/12 bronze prop from a 1930's Chris-Craft. I have a 1973 307 in good condition that has been in the corner of my shop for the last 40 years. I pulled it apart today and found it would just need a cam, rings and a valve job. I was thinking I should upgrade the pistons, but since the 307 isn't a popular performance motor there are no hypereutectic or forged pistons available. Did the 307 marine engines have better pistons than the factory automotive ones? should I even worry about cast pistons in this small a boat? I have an early 265 Chevy engine no oil filter no side engine mounts . I also have a new 4 bolt main Goodwrench 350 I pulled from the Chris-Craft.
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307 Marine Engine question
- Thread starter rocco611
- Start date
I thought about using the 350 but it would use more fuel and be way more horsepower than the boat needs. I plan on buying a mild marine cam for the 307 . I used to get cams ground by Chet Herbert, unfortunately he past away in 2009 . he ground circle track, drag race and street cams for me. I won a lot of races with his parts and advice. every time someone passes away a library closes.
gonzo
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For marine use a cam with a flat torque curve starting at relatively low RPMs is what you need. Boat plow through the water and don't accelerate to speed and then let off the throttle. It is the equivalent to a fully loaded car going a steep uphill at high speed. Running a marine engine at 3500 RPM is being very moderate. By comparison, my 3/4 ton van drives 70 MPH at around 2300RPM. That equates to 98 MPH uphill fully loaded. The 307 will have plenty of power. Is that a Pontiac, Olds or Chevy?
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