The rebuild kit for the AFB carb contains 3 gaskets for use between carb and manifold. The assembly manual is not clear on which gaskets to use. Your suggestions are always appreciated.
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Re: Gaskets for AFB on '63 340
Peter----
The gasket has 4 equal size holes and NO heat groove (as do the 300 hp gasket). If it's totally of original configuration, it will have a small rectangular "tab" on the front of the gasket.In Appreciation of John Hinckley -
Re: Gaskets for AFB on '63 340
Peter----
The gasket has 4 equal size holes and NO heat groove (as do the 300 hp gasket). If it's totally of original configuration, it will have a small rectangular "tab" on the front of the gasket.In Appreciation of John HinckleyComment
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I Disagree
The secondary holes are a tad larger.
The 300 Hp gasket set consisted of a galvanized heat shield, chaneled phonelic spacer and chaneled gasket.
Dale.Comment
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I Disagree
The secondary holes are a tad larger.
The 300 Hp gasket set consisted of a galvanized heat shield, chaneled phonelic spacer and chaneled gasket.
Dale.Comment
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Here's my take on the deal
The gasket I have for my 340 has slighly larger secondary openings to match the the AFB's larger secondary throttle bores, which are 1 11/16" versus the 1 9/16" primaries. The 340 HP gasket is unique to that engine configuration as it has no heat riser slot.
As Dale said, the 300 HP configuration consisted of a gasket with a heat riser slot, phenolic insulator (with a heat riser opening, matching the gasket plan form), and a stainless steel shim (without the heat riser slot as it acted at a heat shield to protect the the aluminum carburetor body from direct exhaust gas heat), which should be installed in that order, bottom to top.
DukeComment
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Here's my take on the deal
The gasket I have for my 340 has slighly larger secondary openings to match the the AFB's larger secondary throttle bores, which are 1 11/16" versus the 1 9/16" primaries. The 340 HP gasket is unique to that engine configuration as it has no heat riser slot.
As Dale said, the 300 HP configuration consisted of a gasket with a heat riser slot, phenolic insulator (with a heat riser opening, matching the gasket plan form), and a stainless steel shim (without the heat riser slot as it acted at a heat shield to protect the the aluminum carburetor body from direct exhaust gas heat), which should be installed in that order, bottom to top.
DukeComment
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Re: Here's my take on the deal
Glad you agree Duke. Are you sure the heat shield was aluminum (good heat conductor)? Mine are galvanized steel.
Dale.Comment
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Re: Here's my take on the deal
Glad you agree Duke. Are you sure the heat shield was aluminum (good heat conductor)? Mine are galvanized steel.
Dale.Comment
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Correction
I meant stainless not aluminum. As I said I've only encountered galvanized steel in my travels.
Dale.Comment
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Correction
I meant stainless not aluminum. As I said I've only encountered galvanized steel in my travels.
Dale.Comment
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Re: Correction
Now you've got me thinking, Dale. Back in the seventies I bought a new 3721S carb from a parts store, and it came with the 300 HP gasket and a galvanized steel heat shield. Sometime before that I bought a gasket, insulator, and spacer from GMPD (I was thinking of adapting the insulator to my 340 engine).
I'm pretty sure the GMPD spacer was stainless. Unfortunately,I'm not exactly sure wherre it is right now.
The insultor won't fit on a 340 due to hood clearance issues.
DukeComment
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Re: Correction
Now you've got me thinking, Dale. Back in the seventies I bought a new 3721S carb from a parts store, and it came with the 300 HP gasket and a galvanized steel heat shield. Sometime before that I bought a gasket, insulator, and spacer from GMPD (I was thinking of adapting the insulator to my 340 engine).
I'm pretty sure the GMPD spacer was stainless. Unfortunately,I'm not exactly sure wherre it is right now.
The insultor won't fit on a 340 due to hood clearance issues.
DukeComment
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