427 Tri-Power carb questions
#1
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427 Tri-Power carb questions
I own a 1969 Corvette with the L-71 427 V-8 fitted with Tri-Power 3x2 carbs. Many questions:
1. I was told that the carb-to-manifold gaskets for the two end (outboard) 2V carburterors are slightly different than the gasket for the center (inboard) 2V carbureteror. Is this true ... and if so does anyone have the part number (Fel-Pro gaskets preferred) for the gaskets?
2. I was told the center carburetor jetting for a L-71 is 62 with a 6.5 power valve. While that may be the factory jets, is there a general consensus on what the center carb jetting SHOULD be? (such as 60, 64 or such)?
3. What are the jetting specs for the two end carbs?
4. What is the name of the screw head that is used to remove the plates mounted inside the float bowls of the two outer carbs on a 3x2 carb setup?
5. Are the L-71's 3x2 2V carb float bowl gaskets the same as a normal Holley 650 cfm 4v carb?
6. What is the part number (Fel-Pro preferred) for vacuum diaphragms fitted to the two 2V end carburetors?
7. What size air bleeds are fitted to the center 2V carb as well as the two outer 2V carbs?
8. Do all of the 1969 Tri-Power 2V carbs feature studs to mount the carbs? (Note: my center carb had two bolts holding the center carb while studs with nuts were used for all the other carb mounting locations).
9. What is the correct PCV valve (a part number would be great) for a 1969 L-71?
1. I was told that the carb-to-manifold gaskets for the two end (outboard) 2V carburterors are slightly different than the gasket for the center (inboard) 2V carbureteror. Is this true ... and if so does anyone have the part number (Fel-Pro gaskets preferred) for the gaskets?
2. I was told the center carburetor jetting for a L-71 is 62 with a 6.5 power valve. While that may be the factory jets, is there a general consensus on what the center carb jetting SHOULD be? (such as 60, 64 or such)?
3. What are the jetting specs for the two end carbs?
4. What is the name of the screw head that is used to remove the plates mounted inside the float bowls of the two outer carbs on a 3x2 carb setup?
5. Are the L-71's 3x2 2V carb float bowl gaskets the same as a normal Holley 650 cfm 4v carb?
6. What is the part number (Fel-Pro preferred) for vacuum diaphragms fitted to the two 2V end carburetors?
7. What size air bleeds are fitted to the center 2V carb as well as the two outer 2V carbs?
8. Do all of the 1969 Tri-Power 2V carbs feature studs to mount the carbs? (Note: my center carb had two bolts holding the center carb while studs with nuts were used for all the other carb mounting locations).
9. What is the correct PCV valve (a part number would be great) for a 1969 L-71?
#2
1. I was told that the carb-to-manifold gaskets for the two end (outboard) 2V carburterors are slightly different than the gasket for the center (inboard) 2V carbureteror. Is this true ... and if so does anyone have the part number (Fel-Pro gaskets preferred) for the gaskets? Here are the gaskets, look the same to me
http://willcoxcorvette.com/product_i...oducts_id=6279
2. I was told the center carburetor jetting for a L-71 is 62 with a 6.5 power valve. While that may be the factory jets, is there a general consensus on what the center carb jetting SHOULD be? (such as 60, 64 or such)? If it's a stock engine look at the carb number on the air horn and then check the Holley listing. http://www.holley.com/data/TechServi...%20Listing.pdf
3. What are the jetting specs for the two end carbs? Look at the carb number on the air horn and then check the Holley listing. http://www.holley.com/data/TechServi...%20Listing.pdf
5. Are the L-71's 3x2 2V carb float bowl gaskets the same as a normal Holley 650 cfm 4v carb? Check the Holley listing above for the number.
6. What is the part number (Fel-Pro preferred) for vacuum diaphragms fitted to the two 2V end carburetors? Again Holley part listing.
9. What is the correct PCV valve (a part number would be great) for a 1969 L-71? Do you have the owners manual?
http://willcoxcorvette.com/product_i...oducts_id=6279
2. I was told the center carburetor jetting for a L-71 is 62 with a 6.5 power valve. While that may be the factory jets, is there a general consensus on what the center carb jetting SHOULD be? (such as 60, 64 or such)? If it's a stock engine look at the carb number on the air horn and then check the Holley listing. http://www.holley.com/data/TechServi...%20Listing.pdf
3. What are the jetting specs for the two end carbs? Look at the carb number on the air horn and then check the Holley listing. http://www.holley.com/data/TechServi...%20Listing.pdf
5. Are the L-71's 3x2 2V carb float bowl gaskets the same as a normal Holley 650 cfm 4v carb? Check the Holley listing above for the number.
6. What is the part number (Fel-Pro preferred) for vacuum diaphragms fitted to the two 2V end carburetors? Again Holley part listing.
9. What is the correct PCV valve (a part number would be great) for a 1969 L-71? Do you have the owners manual?
Last edited by MelWff; 10-02-2012 at 11:05 AM.
#3
Drifting
[QUOTE=Corvette Kiwi;1581971385]I own a 1969 Corvette with the L-71 427 V-8 fitted with Tri-Power 3x2 carbs. Many questions:
1.
Fel-Pro part # 60070
2.
66 jets in mine with a 6.5 power valve at 50' above sea level. Dialed in using an AFR meter.
3.
No jets in the outboard carbs, they have metering plates. Metering plates with larger/smaller sizes are available.
4.
I use a pilot head screw bit (butterfly bit) on the metering plates
5.
Same gasket as far as I know.
6.
Don't believe Fel-Pro makes the diaphragms. Holley OEM is your best bet.
7.
Not able to answer without refering to my notes at home.
8.
The studs that are below the fuel-line to carb connection are shorter. The fuel-lines curve down and if the studs are to long the line hits and will not seat into the inlet fitting.
9.
A/C-Delco part # 6484525 or Standard Motor Products V-160
1.
Fel-Pro part # 60070
2.
66 jets in mine with a 6.5 power valve at 50' above sea level. Dialed in using an AFR meter.
3.
No jets in the outboard carbs, they have metering plates. Metering plates with larger/smaller sizes are available.
4.
I use a pilot head screw bit (butterfly bit) on the metering plates
5.
Same gasket as far as I know.
6.
Don't believe Fel-Pro makes the diaphragms. Holley OEM is your best bet.
7.
Not able to answer without refering to my notes at home.
8.
The studs that are below the fuel-line to carb connection are shorter. The fuel-lines curve down and if the studs are to long the line hits and will not seat into the inlet fitting.
9.
A/C-Delco part # 6484525 or Standard Motor Products V-160
#4
Race Director
Fordman
Was the 66 jets WOT or cruise? What afr was your goal? Was there surging or mis before?
Did the PVCR need to be changed?
Thanks! I'm taking notes.
Was the 66 jets WOT or cruise? What afr was your goal? Was there surging or mis before?
Did the PVCR need to be changed?
Thanks! I'm taking notes.