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Old January 27th, 2019, 11:23 PM
BillT BillT is offline
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Join Date: Jan 2013
Location: Moneta, VA
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Default Re: Terrible gas mileage,

Quote:
Originally Posted by jagarra View Post
Mine has the stock exhaust system, 2 into one with a muffler.
Is the Muffler the original GMC V-6 type? There is a chance that it won't be because they have been dis-continued for many years now. I wouldn't run anything less than a Straight-Thru. A Cherry Bomb now made by Thrush is a good replacement. As mentioned earlier it's very important for these engines to breathe and to get the Mileage that they should be achieving.
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Drove and owned many, but some of the more interesting ones were:

-'60 GMC 2500 Dump, 305 V-6
-'62 GMC 4000 Flatbed, 305 V-6
-'62 GMC 6500 Flatbed Dump, 478 V-6
-'67 GMC 7500 Box, 6V-53 Detroit
-'71 GMC 9500 Flatbed Dump, 637 V-8
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