Need speedo / gear help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bucket · 03-27-2021, 11:59 AM

I have a 79 K10 with 1/2 life 33 BFG AT KOs. 350/350/NP203. The 203 has been converted to part time and it has a 1:3000 ratio adapter on the speedo cable. The speedo reads little less than 10% fast (75 @ GPS 70). On the highway the odometer measures almost exactly 9 miles over 10 miles per mile markers. I have not pulled covers on the axles but I'm guessing they have been changed. My RPMs are about 2400 at GPS 70. I think they would be lower than this if the original 3.07 gears were in there. What gearing do you guys think I have? Is there another ratio adapter box that would get my speedo / odo more accurate?

03-27-2021, 11:59 AM	#1
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	Need speedo / gear help I have a 79 K10 with 1/2 life 33 BFG AT KOs. 350/350/NP203. The 203 has been converted to part time and it has a 1:3000 ratio adapter on the speedo cable. The speedo reads little less than 10% fast (75 @ GPS 70). On the highway the odometer measures almost exactly 9 miles over 10 miles per mile markers. I have not pulled covers on the axles but I'm guessing they have been changed. My RPMs are about 2400 at GPS 70. I think they would be lower than this if the original 3.07 gears were in there. What gearing do you guys think I have? Is there another ratio adapter box that would get my speedo / odo more accurate? __________________ 79 K10 77 MGB 79 Kawasaki KZ1000



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