Author Topic: Quad Air Horns Interchangeable ?  (Read 1155 times)

Offline MBP

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Quad Air Horns Interchangeable ?
« on: February 16, 2023, 07:57:00 PM »
Hello to all. I have a bit of a problem and a question. I have a 1969 Rochester Quad.#7029207 that has a Air Horn with # 7037307. not sure if the different numbers mean that they aren't matching from date of manufacture. Doesn't really matter because they seemed to work well together. Unfortunately a part was broken off and may well leave the horn unusable. Will try to fix but not to hopeful.
I do have another Air horn, from a 68 I believe, Air Horn #7032741.
I can only see one physical difference but that shouldn't be a problem hopefully. My question is are these Air Horns interchangeable as to the vents and other "internals" Thanks and take care.

Offline Kenth

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Re: Quad Air Horns Interchangeable ?
« Reply #1 on: February 17, 2023, 01:36:32 AM »
Check for upper idle airbleed location, secondary POE and air valves opening rate, other than that it should work.

Offline MBP

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Re: Quad Air Horns Interchangeable ?
« Reply #2 on: February 17, 2023, 07:43:58 AM »
Thanks for your reply Kenth. I'm sorry but my knowledge of the carburetor is very limited. Hate to say it but the things you have mentioned have gone right over my head.
Do you mean the Idle vent at the front and not sure what the secondary POE and air valves are. Are they called by another name or what does POE stand for? Again, sorry for my confusion and thanks again.

Offline Kenth

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Re: Quad Air Horns Interchangeable ?
« Reply #3 on: February 17, 2023, 10:38:37 AM »
Ok, then you have an exciting learning period ahead of you.
I recommend a copy of cliff's book.

https://cliffshighperformance.com/product/how-to-rebuild-and-modify-rochester-quadrajet-carburetors

Offline von

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Re: Quad Air Horns Interchangeable ?
« Reply #4 on: February 18, 2023, 06:26:28 AM »
I second the suggestion to get Cliff's book. When joining mismatched castings I recommend studying every internal air and fuel passage, where they go and and up, and what they do. Then you can determine the compatibility of each.

Offline MBP

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Re: Quad Air Horns Interchangeable ?
« Reply #5 on: February 20, 2023, 07:36:42 AM »
Thanks for the replies. I do have Cliff's book and it is essential. What I wondered about that isn't mentioned in the book is a grove on the bottom side just to the beside of the idle vent valve flapper. I'm thinking that is perhaps for the float hinge pin. There is also a part in the casting also on the bottom by the float vent tube that has a 45 degree angle on the 69 but straight sides on the 68. All the holes line up and size out the same. I suppose one way to find out is to simply put it on and try it.