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I am restoring a 74 Corvette and the original EFE unit snapped off when trying to remove it from the crusty thermostat housing. I bought a new one which looked like the correct part. When it arrived, though, I noticed it has an extra nipple so a total of 3 nipples rather than the original's 2. They sent me the wrong part I believe. I didn't buy a 75+ version because it seems to include an electronic switch that the original did not.
Questions:
1. Can I use this new unit and just block off one of the tubes?
2. Which tube can be blocked off?
3. Which tubes are supposed to go to which spots on the vacuum system?
I've attached some images of the new unit and of the '74 assembly manual in relation to the EFE unit (which clearly shows the 2 nipple version).
Thanks in advance for the help. This forum has been integral in doing this restoration.
Last edited by HLFReindeer; Mar 22, 2024 at 10:47 AM.
I am restoring a 74 Corvette and the original EFE unit snapped off when trying to remove it from the crusty thermostat housing. I bought a new one which looked like the correct part. When it arrived, though, I noticed it has an extra nipple so a total of 3 nipples rather than the original's 2. They sent me the wrong part I believe. I didn't buy a 75+ version because it seems to include an electronic switch that the original did not.
Questions:
1. Can I use this new unit and just block off one of the tubes?
2. Which tube can be blocked off?
3. Which tubes are supposed to go to which spots on the vacuum system?
I've attached some images of the new unit and of the '74 assembly manual in relation to the EFE unit (which clearly shows the 2 nipple version).
Thanks in advance for the help. This forum has been integral in doing this restoration.
The TVS switch you are holding is a more modern design.
If you look closely to your original there should be vents (exhaust port) on the side of the switch. The lower port on the new switch serves that function. Leave that port open as trapped energy needs a place to escape.
Looking at your photos of the AIM there were 3 different TVS switches used...
#1. GM #3030200
Optional GM #342763 or SMP #PVS13
Optional GM #342764
If you go to ebay and do a search for SMP PVS13 you will see the gills on the side I explained above...
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
74 EFE TVS Extra Nipple
