Holley help

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mopar head

mopar head

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I`m trying to break apart a Holly 750 double pump carb, been setting on car for about 12 years. Removed the 4 fuel bowl bolts, and it won`t budge, tried tapping with rubber malet, nothing. Am I missing any bolts? or do these things stick pretty bad sometimes? Hate to break something. First time messing with holleys. :help:
 
mopar head said:
So some more good wacks with malet?
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They do stick if they have been on awhile. It doesn't take twelve years. I use a flat paint scraper or thin gasket scraper and lightly tap it in between the carb body and the bowl. Be gentle as you don't want to scar up the joining surfaces any more than necessary. The real fun is taking off the old gasket material. When you put it back together use the blue re-usable gaskets and they won't stick. Makes it easy to do jet changes, float adjustments and the bowls will just about fall off when you take out the bolts and you just use the same gaskets over and over. Good luck.
 
Thanks, I finally got one off, Man, It was like it was glued on, and you ain`t kidden about getting gasket materal off. I sprayed with WD, maybe that will soften it up, and try later. Im thinking dremel with nylon bristle brush, but I`m out, restock time! Curious with float, It only lifted 1/8" off floor of bowl until seating, Normal? or could I of bent tab, by wacking with malet? Bowl looked spotless inside, Worth taking secondary bowl off? Should I change pump diaghrams? Seen no #`s on jets but have`nt removed them, I thought they have small #`s on them. Would like to try to tune to my 69 340. Any thoughts of this carb being too much for my combo? Dont want to spend a bunch of money, cause its a loaner with option to buy, from brother. Any good ballpark figures on jet sizes? Thoughts on blocking secondary pump? and how is this done, A cap? This carb is a socalled HP modified from unknown source, Milled horn, and nice looking squirters. any guidence would be apreciated. I know I`ll have to spring for gaskets, but I have access, to kit with jets and cams. All ears:-D
 
mopar head said:
Thanks, I finally got one off, Man, It was like it was glued on, and you ain`t kidden about getting gasket materal off. I sprayed with WD, maybe that will soften it up, and try later. Im thinking dremel with nylon bristle brush, but I`m out, restock time! Curious with float, It only lifted 1/8" off floor of bowl until seating, Normal? or could I of bent tab, by wacking with malet? Bowl looked spotless inside, Worth taking secondary bowl off? Should I change pump diaghrams? Seen no #`s on jets but have`nt removed them, I thought they have small #`s on them. Would like to try to tune to my 69 340. Any thoughts of this carb being too much for my combo? Dont want to spend a bunch of money, cause its a loaner with option to buy, from brother. Any good ballpark figures on jet sizes? Thoughts on blocking secondary pump? and how is this done, A cap? This carb is a socalled HP modified from unknown source, Milled horn, and nice looking squirters. any guidence would be apreciated. I know I`ll have to spring for gaskets, but I have access, to kit with jets and cams. All ears:-D
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The jets will have a number on them, on the side. You will be able to see it when you take one out. You will probably have something in the area of 72-78 It is hard to say what you will have to do. I can tell you that you won't notice any significant change with any less than a 3 increment change in jet size. 69 to 72 for example. Any less than 3 # change will come with alot of fine tuning. The gasket a a cheap investment, less then 10bucks. It is possible that a 750 might be a little much for a stock 340 you will just have to feel it out. If you go on the Holley web site you can look up the mdl # that is on the horn of the carb and then you will know what that carb had in it from the mfg. That info will help you know if it was modified as claimed. I have worked over 318 and I am running a 600cfm with 72 jets. I had a 750 double pump, it was to much for my set up. Trial and error. Good luck.
 
Unless you have a 4-speed car, the double pumper might end up being a little much for you. Now, a 750 vaccum secondary would probably work well for you.

I would replace all the seals and diaphragms if you already have them.
 
Thanks responders. I`ve decided to get bowl gaskets to button it back up, and return to brother. He will not take a significate loss to justify, purchess, a rebuild and retune, to gain any performance over my 750 st. avenger. I`ll forgo a little performance, in exchange for a sane fuel economy8)
 
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