How accurate is my Speedo? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

greg72 · 05-27-2003, 03:31 AM

I changed from a Muncie M-22 to a TH350. The TH 350 came out of a Malibu. Is this properly geared to give me a reasonably accurate speed?

Project1970 · 05-27-2003, 06:01 AM

There's not even close to enough information to know whether or not that'll be right; to know, we'd have to know the tire sizes and rear end ratios of both cars, or the RPMs at an indicated speed in 3rd gear, tire size, and rear end ratio for the truck now.

mrein3 · 05-27-2003, 07:36 AM

The best way to check your speedo is against a GPS. Just about everybody has one now. Find a pal with one and ask him to go for a drive.

Longhorn Man · 05-27-2003, 07:45 PM

Being that your in Cali, the state will fix this for you. Talk to your local inspection station, and if they are clueless, call the police. I know this is practiced in Southern Cali, and it is a state funded ordeal.

greg72 · 05-27-2003, 10:39 PM

thanks for the help. It is really appreciated.

05-27-2003, 03:31 AM	#1
greg72 Registered User Join Date: Dec 2002 Location: Central California Posts: 88	How accurate is my Speedo? I changed from a Muncie M-22 to a TH350. The TH 350 came out of a Malibu. Is this properly geared to give me a reasonably accurate speed? __________________ Greg72

05-27-2003, 06:01 AM	#2
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	There's not even close to enough information to know whether or not that'll be right; to know, we'd have to know the tire sizes and rear end ratios of both cars, or the RPMs at an indicated speed in 3rd gear, tire size, and rear end ratio for the truck now. __________________ Project1970 - LS1 Swap Complete!

05-27-2003, 07:36 AM	#3
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	The best way to check your speedo is against a GPS. Just about everybody has one now. Find a pal with one and ask him to go for a drive. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

05-27-2003, 10:39 PM	#5
greg72 Registered User Join Date: Dec 2002 Location: Central California Posts: 88	thanks thanks for the help. It is really appreciated. __________________ Greg72

05-27-2003, 07:45 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Being that your in Cali, the state will fix this for you. Talk to your local inspection station, and if they are clueless, call the police. I know this is practiced in Southern Cali, and it is a state funded ordeal.



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