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Thu, 08 April 2010 10:15  |
Hot wheels
Messages: 9
Registered: April 2010
Location: Holiday City Ohio
Karma:
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Junior Member |
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Good Morning,
I have been working latley on the old 77 palm beach that has been in our fammily since about 1978. I'll give you the long and short versions of the story.
I'm 42, grew up seeing the states in the 77 PB dad owned, we put 250k on the old thing over the years and have upgraded just about everything. Sway bars, bilstiens, 3 bearing hubs, 4 bag air, alcoas and rear disk brakes, new rear frame and the lower 3.50 drive gears has a custom pain job as well. I have put 2 rebuilds on the old 455 and the most recent one a year ago with a new throttle body fuel injection system. I sold my low mile (69k) '76 elegonza when Dad decided to move into an 86 prevost and spend more time living in one winters in FLA. I have been working on these, swapping motors and repairs since i was 16 helping the rv seating company we worked for keep a small fleet of them running as seating show vehicles. I have spent way more time in and around these things than most can imagine.
Anyway I picked up dads 77 and decided it was time to freshen the engine and trans and add a fuel injection system to try and get the most out of it both in power and fuel milage. I have spent the last year fighting overheating problems that it never had before and very poor milage. I think i finally found the source of the heating problem after installing a new griffen radiator and flow cooler pump I still had the problem, i found one of the chambered mufflers was broken and plugging the outles partially and making it build heat the harder i ran it. A good pair of glass pack mufflers really brought the engine back around and seems to have gotten rid of the heating problem. I usually pull a 14x7 enclosed trailer around with me so im used to poor milage but on the last shake down run I got 4.8 mpg., up from 3.5 the previous run, set at a constant 65mph. I think I have the injection tuned pretty well now but the lower gear and faster highway speeds may be taking a toll on me. We used to get around 7 pulling the trailer @ 65 or a little less. at 2700 rpm down the road I think i need to go back to the higher gear and get the rpm back down a little.
Is anyone running a simular setup, have any thoughts on the milage? I also have been digging around a little here and see a couple referances to a 6.5 diesel conversion that has been done. If i could find out a little more about who and how it works I would be reateful. I really love this old gmc but im having a hard time accepting that i cant get to 10mpg pulling a pretty small trailer around. i know its alot to ask for, we used to get 9.8 as best ever running 55 mph with taller tires and no trailer. the speed increase alone probably costs me 1-2 mpg then add the trailer gets me down to 7 but 5? Im a little frustrated i guess and looking for options to keep this a usable viable unit for my family. we are running 100-150 miles each way to karting events and such and I get really frustrated at haveing to fuel at both ends of the trip.
I have a picture of it floating around here somewhere i'll see if i can post it up.
Sean Rupp
Holiday City Ohio
[Updated on: Thu, 08 April 2010 10:52] Report message to a moderator |
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