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**hatzie** · 02-04-2013, 01:04 AM

The smaller diameter sender used on later '80s engines is not calibrated for the 74-78 temp gauge.
I've read about guys turning the threaded portion of the '80s sender down in a lathe and re-threading it to match the later model metric sender on the LS engines.
You might be able to drill out and re-tap the sender boss in the cylinder head. I'd be extremely careful to closely examine that boss... to ensure there's enough meat in the casting to get away with that.
You could put the 74-78 temp sender in the intake manifold coolant crossover heater hose connection and live with the fact that it runs slightly cooler there.
You could swap in a 1979 temp gauge and use the smaller diameter 1350 ohm 1980's sender in the head.

02-04-2013, 01:04 AM	#5
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,920	Re: Temp sender and Shift Linkage Qs. The smaller diameter sender used on later '80s engines is not calibrated for the 74-78 temp gauge. I've read about guys turning the threaded portion of the '80s sender down in a lathe and re-threading it to match the later model metric sender on the LS engines. You might be able to drill out and re-tap the sender boss in the cylinder head. I'd be extremely careful to closely examine that boss... to ensure there's enough meat in the casting to get away with that. You could put the 74-78 temp sender in the intake manifold coolant crossover heater hose connection and live with the fact that it runs slightly cooler there. You could swap in a 1979 temp gauge and use the smaller diameter 1350 ohm 1980's sender in the head. __________________ 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.