Eagle four inch cast steel crank, Eagle rods, 4.04 bore with KB quench dome pistons equals 410 cubic inches in a 360 block. The compression ratio is 10.5 to 1. Since my cruising rpm range isn't that high at 3000-3600, there's really not that much stress on it so I didn't need to get expensive forged pistons or a forged crank. The cam was custom ground by Dave Hughes www.hughesengines.com for peak torque at 2500 rpm. I did that because that's when the maxium load is when the boat's trying to climb up on step. According to my desk top dyno program I have 505 lb-feet of torque at 2500 and more than 450 lb-ft from 2000 to 5000. I didn't build a hot rod so much as a tractor motor with a wide power band. The high compression ratio was for fuel efficiency more than horsepower. The cooling systems on these Chrysler marine engines are pretty good, and with me running in water that is pretty consistently cold year round I wasn't that worried about detonation issues. I run a 180 degree thermostat (stock for a fresh water cooled engine is 160, raw water cooled engines were 140) and my temperature stays about 130 degrees no matter how long I run it. I got some aluminum gas tanks made to fill the available space and my bunker is now 136 instead of 100 gallons. In my humble opinion, the 27 is at it's best cruising 15-18 knots in a two or three foot chop. The boat is heavy for its size and has a fairly sharp entry so it's really comfortable in choppy water. You will run right by the aluminum runabouts and lightweight Bayliners that can't take the pounding. Chrysler made a great marine engine and it will live a long time running 3000-3800 rpm. Run the crap out of it!
John --- On Fri, 9/11/09, dodgetkboy78 <[email protected]> wrote: From: dodgetkboy78 <[email protected]> Subject: [UnifliteWorld] Re: Prop pitch, GPH, cruising speed, RPM To: "UnifliteWorld" <[email protected]> Date: Friday, September 11, 2009, 5:06 PM "I rebuilt my engine in my garage with more compression, longer stroke crank, custom camshaft, other goodies. Standard rotation engine now, lightened 250 pounds and set back about four inches, ZF63A transmission, 1.5 to 1 ratio, 16x16 RH prop. Minimum planing speed same 13 knots, cruising speed up to 19 knots at the same 3400 rpm, top speed up to 30 knots at 5000 rpm. With bigger custom gas tanks I now have 60% more range with my cost per mile down 50 cents despite higher priced 91 octane gas." What stroke crank did you use? I have a 318 in my truck stroked to a 390, 4"x3.34. The issues I have had with it just being a work truck motor, I am not sure I could trust it in a boat. Well, crap pistons from KB had something to do with it. Just curious what was in your 360. >From the sounds of it, I should find and build me a 273, and just plan on running it in displacement. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "UnifliteWorld" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/unifliteworld?hl=en -~----------~----~----~----~------~----~------~--~---
