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Spreadbore Carb?

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Got a rebuilt "86" 5.0 w/ Offenhauser spreadbore intake. Engine internals unknown. 600 cfm Holley square bore w/ proper adapter plate, gaskets etc. Half a** rebuilt myself and a mechanic went back thru it, but it still just ain't right. Would like to buy a carb to match the intake to gain any advantage that a previous owner might have had in mind. Any suggestions on what to get? Tired of messing with this thing. It's in a 77 w/ a C4 so need the Ford kickdown linkage compatable. Yes, I know it's the wrong intake for a 4x4.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
Q-jet on a Port-o-sonic should be a great combo. I liked the port-o-sonic I had on the 351 but lost it while tuning the engine with different parts (chasing down a bad carb). The C4 kickdown will take a little work to make right, but it should be worth it.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
Whats not right with your current setup? Doubt its the wrong manifold for a 4x4 unless its a single plane. I finally took my edelbrock 289 torker(single plane) off my 302 and seemed to get a improvement but I havent fully tuned and tested it yet. I had the torker running great but it did take some tuning. While a spread bore carb may give you better throttle response it will probably still need to be tuned and may not be worth spending the $$ to swap over IMO. Doubt you will really see any performance gain especailly with a qjet as they are not a perfromance carb and few people can actaully get them to run much less tune them if needed.
Holley did/does make a spread bore carb that replaces the qjet might find a used one for cheap. Qjets run good when they run and are junk when they dont.
 
OP
OP
Explorer

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Whats not right with your current setup? Doubt its the wrong manifold for a 4x4 unless its a single plane. I finally took my edelbrock 289 torker(single plane) off my 302 and seemed to get a improvement but I havent fully tuned and tested it yet. I had the torker running great but it did take some tuning. While a spread bore carb may give you better throttle response it will probably still need to be tuned and may not be worth spending the $$ to swap over IMO. Doubt you will really see any performance gain especailly with a qjet as they are not a perfromance carb and few people can actaully get them to run much less tune them if needed.
Holley did/does make a spread bore carb that replaces the qjet might find a used one for cheap. Qjets run good when they run and are junk when they dont.
Yea, it is a single plane. Been looking at that Holley, 0-80555. It's a 650cfm, a little large, but may work. Wish I knew what cam was in it. I'm alway's trying save a little when I can and would like to find a good used one. I'll post in the want ad's. Thanks Guy's
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
I'd suggest getting a dual plane manifold. before getting a new carb you can usually find them used for pretty cheap even new ones are only about 1/2 the price of a carb. The single planes take a lot of carb tinkering to get right. I'm not sure a qjet is a good idea with a single plane just because they are very hard to tune. The holley spread bore may be more tuneable due to readily availible parts. Spead bore carbs are usually bigger than normal 650 is a small spread bore Most qjets are usually 750 cfm to 850 cfm. but like all vac secondary carbs your really only using as much air as the engine needs.
Like I said I just replaced a single plane on my bronco with a dual plane it seemed to pick up some low end power and I havent done any rejetting yet as it seems to be running great. I've only run it around town so far but I need to take it out on the hiway and up some hills to see how its really running.
 
OP
OP
Explorer

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Found the carb in a local sale paper. This one is my son's Bronco so I asked before buying it. Said it straightend out so reckon we'll deal with it later. Least I know now what to do. Thanks again guy's.
 
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