tachometer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**hatzie** · 08-26-2014, 11:07 PM

Get a complete unit.
73-75 Ammeter mechanical oil pressure Don't use on other years unless you like electrical fires. The 73-75 tachs are less than reliable and potted so the boards can't be repaired just replaced.
76 Volt meter and mechanical oil pressure
77-80 Volt Meter and Electric oil pressure. 100mph speedo dropped to 85mph sometime in this range.
81-89 larger tan font different color needles and mechanical speedo maybe 81-90?
90-91 electric speedo... Maybe only 1991?
Sometime in the 88-91 R/V squares there was a mechanical speedo with trip odometer.

The medium duty 40-60 trucks have tachs with fuel gauges on the bottom so you could put a clock in the lower left corner hole.

Be sure to get a V8 or I6/V6 tach whichever you have... and be sure to avoid the MD diesel tachs.

08-26-2014, 11:07 PM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,050	Re: tachometer Get a complete unit. 73-75 Ammeter mechanical oil pressure Don't use on other years unless you like electrical fires. The 73-75 tachs are less than reliable and potted so the boards can't be repaired just replaced. 76 Volt meter and mechanical oil pressure 77-80 Volt Meter and Electric oil pressure. 100mph speedo dropped to 85mph sometime in this range. 81-89 larger tan font different color needles and mechanical speedo maybe 81-90? 90-91 electric speedo... Maybe only 1991? Sometime in the 88-91 R/V squares there was a mechanical speedo with trip odometer. The medium duty 40-60 trucks have tachs with fuel gauges on the bottom so you could put a clock in the lower left corner hole. Be sure to get a V8 or I6/V6 tach whichever you have... and be sure to avoid the MD diesel tachs. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 08-26-2014 at 11:14 PM.



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