68 won't go passed 60mph - The 1947 - Present Chevrolet & GMC Truck Message Board Network

JonCheun · 01-05-2013, 05:18 PM

I have a 1968 C10 Stepside w/ a 350 crate engine that has 15000 miles and gear vendor overdrive. I just put a new Holley manual choke 2 barrel carb on it. Yesterday I was on the interstate and when I got up to 65mph it would hold but then start to jerk and go down to 55mph then to 50mph. It runs fine when I am on surface streets and going only up to 45mph but once I go to 60mph it starts to do it again. Today, I'm going to change the spark plugs.

Anyone Have any ideas or have experienced this same problem.

-Jon Cheun

**VetteVet** · 01-05-2013, 08:43 PM

Symptoms of a bad fuel pump unless it ran fine before the carb change. The main jets in the carb might be too small as well.

01-05-2013, 05:18 PM	#1
JonCheun Registered User Join Date: Jan 2013 Location: Las Vegas,NV Posts: 59	68 won't go passed 60mph I have a 1968 C10 Stepside w/ a 350 crate engine that has 15000 miles and gear vendor overdrive. I just put a new Holley manual choke 2 barrel carb on it. Yesterday I was on the interstate and when I got up to 65mph it would hold but then start to jerk and go down to 55mph then to 50mph. It runs fine when I am on surface streets and going only up to 45mph but once I go to 60mph it starts to do it again. Today, I'm going to change the spark plugs. Anyone Have any ideas or have experienced this same problem. -Jon Cheun

01-05-2013, 08:43 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,709	Re: 68 won't go passed 60mph Symptoms of a bad fuel pump unless it ran fine before the carb change. The main jets in the carb might be too small as well. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.



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