Where do these go?
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
pic 1, power for the idle stop solenoid. should be mounted on the side of the carb and pushes on the throttle lever, yours is missing.
pic2, thermostatic vacuum valve, probably goes to the egr valve that is right behind it and is plugged with a hose/bolt. other port of valve goes to the front of carb. probably a port on the front of it that is plugged off.
pic2, thermostatic vacuum valve, probably goes to the egr valve that is right behind it and is plugged with a hose/bolt. other port of valve goes to the front of carb. probably a port on the front of it that is plugged off.
Last edited by H P Bushrod; Oct 4, 2010 at 09:58 AM. Reason: nsv link removed
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
The wire is for the idle stop solenoid which is not installed. It bumps up idle RPMs when the A/C compressor kicks in.
That device is a thermal vacuum switch (TVS). It provides vacuum to the EGR valve when the engine reaches a certain temperature (the switches are normally color-coded as to temp opening). The pic shows a SB but the principles are the same. Note the hoses to the EGR and to the carb. That 45* spout at the base of the carb provides ported vacuum: no vacuum to EGR at idle. In other words the EGR is non-functional at idle.
Thus the TVS is bi-modal; responding to temperature and carb vacuum conditions.
Your EGR system is obviously disabled for some reason.
That device is a thermal vacuum switch (TVS). It provides vacuum to the EGR valve when the engine reaches a certain temperature (the switches are normally color-coded as to temp opening). The pic shows a SB but the principles are the same. Note the hoses to the EGR and to the carb. That 45* spout at the base of the carb provides ported vacuum: no vacuum to EGR at idle. In other words the EGR is non-functional at idle.
Thus the TVS is bi-modal; responding to temperature and carb vacuum conditions.
Your EGR system is obviously disabled for some reason.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
I am not familiar enough with BB engines to know if it has a transmission controlled spark (TCS) system. The TVS and EGR can be ordered at a NAPA (or similar) store. The EGR is unique to 1973-74.
The engine looks basically stock so one has to wonder why the EGR is blocked off. As well I do not see a distributor vacuum advance??
The engine looks basically stock so one has to wonder why the EGR is blocked off. As well I do not see a distributor vacuum advance??
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Feb 2007
Posts: 273
Likes: 0
From: NAPLES FLORIDA
I just bought a 74 LS-4 4spd. And I love it. However upon removing the air cleaner I noticed that there were a couple of electrical clips that were left unplugged. And Plus, whats on the top of the thermostat housing...and where are those hoses supposed to go. I've attached pics, so...does anyone know where these go? Hit me back.
Peeps
Peeps
THE PICS EXPLAIN THE HOSES...THE TOP HOSE GOES TO THE EGR AND THE BOTTOM HOSE CONNECTS TO THE CARB ON THE LOWER PASSENGERS SIDE FRONT
