Carb spacer plate
Thread Starter
Race Director
Joined: Jan 2007
Posts: 10,684
Likes: 696
From: Danville Illinois
2025 Corvette of the Year Finalist - Modified
2024 C3 of the Year Winner - Modified
2021 C3 of the Year Finalist - Modified
2019 C3 of Year Finalist (appearance mods)
Carb spacer plate
I have been running this spacer plate for some 30 years on my old carb trying to reduce the heat because of peculation in the float bowls after shut down.
Well it it doesn't work very well.
New manifold and new carb and want to something new.
Plan B is to install a 5/8 or 1" spacer, i have lots of room under the hood.
Whats the best insulator, wood, plastic,aluminum?
Anybody try this and did it work to control the heat, and what effect did it have on performance.
350, th400, 308 gear, top end mods.
Well it it doesn't work very well.
New manifold and new carb and want to something new.
Plan B is to install a 5/8 or 1" spacer, i have lots of room under the hood.
Whats the best insulator, wood, plastic,aluminum?
Anybody try this and did it work to control the heat, and what effect did it have on performance.
350, th400, 308 gear, top end mods.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
A phenolic spacer like this is the best for heat insulation. I run one on my avatar car. They come in different heights and you can use an open design like this or a 4 hole design. Mine actually improved throttle response but you'll want to research what would be best for your motor combo.
http://www.summitracing.com/parts/SUM-G1405/?rtype=10
http://www.summitracing.com/parts/SUM-G1405/?rtype=10
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
I tried a similar heat shield,still had fuel boil after shutdown hard to restart.Did an air gap manifold swap that blocked the heat crossover from the heads and separates the runners from the valley.No more fuel boiling.I'm in Hawaii so no cold weather here.You might try the phenolic spacer and the heat shield together.Watch hood clearance,I have a drop base air cleaner.
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Thread Starter
Race Director
Joined: Jan 2007
Posts: 10,684
Likes: 696
From: Danville Illinois
2025 Corvette of the Year Finalist - Modified
2024 C3 of the Year Winner - Modified
2021 C3 of the Year Finalist - Modified
2019 C3 of Year Finalist (appearance mods)
Next question.
Manifold is Edelbrock 2701, carb is 4160, vac secondary's, p/n 1850.
Searched lots of chevy related forums, most suggest a 1/2 spacer, ans say it does control the heat.
Options now are go to an open or four hole spacer
Manifold is Edelbrock 2701, carb is 4160, vac secondary's, p/n 1850.
Searched lots of chevy related forums, most suggest a 1/2 spacer, ans say it does control the heat.
Options now are go to an open or four hole spacer
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
Fuel pump?
Mod75,
What fuel pump are you running? The factory pump had a provision for connection to the fuel tank return line. The engineers at GM knew that by keeping the fuel moving, there was little if any percolation. I wouldn't be surprised if you've got an aftermarket FP with no provision for a return line connection. If so, fit a factory pump and reconnect the return line to it. Plus, you can get rid of the shield and you won't need a spacer.
If you have to fit a spacer, then aluminum is definitely not the one to use.
Regards from Down Under.
aussiejohn
What fuel pump are you running? The factory pump had a provision for connection to the fuel tank return line. The engineers at GM knew that by keeping the fuel moving, there was little if any percolation. I wouldn't be surprised if you've got an aftermarket FP with no provision for a return line connection. If so, fit a factory pump and reconnect the return line to it. Plus, you can get rid of the shield and you won't need a spacer.
If you have to fit a spacer, then aluminum is definitely not the one to use.
Regards from Down Under.
aussiejohn
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
GM's solution was to use a 1/4" thick composite, gasket.
I had same problem, by adding the 1/4" gasket
my carb. temp. dropped almost 100 degrees, problem solved.
metal to metal transfers the heat, you need an Insulator,to stop the heat transfer to the carb.
do this simple test, after running up to normal operating temp.
put your hand on the carb, bet you cannot keep it on there very long,
after adding the 1/4" gasket, the carb remains "Cold".
I had same problem, by adding the 1/4" gasket
my carb. temp. dropped almost 100 degrees, problem solved.
metal to metal transfers the heat, you need an Insulator,to stop the heat transfer to the carb.
do this simple test, after running up to normal operating temp.
put your hand on the carb, bet you cannot keep it on there very long,
after adding the 1/4" gasket, the carb remains "Cold".
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Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Don't forget the washers under the nut on the carb bolts.
You can add some more heat isolation using fiber/composite or synthetic washers under the card bolt heads (or nuts if using studs to mount carb). Most specialty hardware stores will have these. Reduces the heat transfer area to just the where the bolt (or stud) touches the carb base.
The cooler the fuel the better,
cardo0
The cooler the fuel the better,
cardo0
Thread Starter
Race Director
Joined: Jan 2007
Posts: 10,684
Likes: 696
From: Danville Illinois
2025 Corvette of the Year Finalist - Modified
2024 C3 of the Year Winner - Modified
2021 C3 of the Year Finalist - Modified
2019 C3 of Year Finalist (appearance mods)
GM's solution was to use a 1/4" thick composite, gasket.
I had same problem, by adding the 1/4" gasket
my carb. temp. dropped almost 100 degrees, problem solved.
metal to metal transfers the heat, you need an Insulator,to stop the heat transfer to the carb.
do this simple test, after running up to normal operating temp.
put your hand on the carb, bet you cannot keep it on there very long,
after adding the 1/4" gasket, the carb remains "Cold".
I had same problem, by adding the 1/4" gasket
my carb. temp. dropped almost 100 degrees, problem solved.
metal to metal transfers the heat, you need an Insulator,to stop the heat transfer to the carb.
do this simple test, after running up to normal operating temp.
put your hand on the carb, bet you cannot keep it on there very long,
after adding the 1/4" gasket, the carb remains "Cold".
Thanks to all for the input.
