blaplante

blaplante

Well Known Member
Ok, perhaps a dumb question, but has anyone messed around with putting the larger O-360 (and O-340) MA-4-5 carb onto a 160 HP O-320? I did find a reference at http://3limafoxtrot.com/maintenance.htm that the MA-4-SPA might run too lean on an O-320. Instead of messing with drilling the jet, why not a bigger carb?

Sorry, I think about this stuff in terms of putting a bigger SU on my MGB!
 
carb

I have heard about this on hot rodded 320's. It would really require the 360 sump to take full advantage of the larger carb. Most of the hot rod engines are injected so this is not very common.
 
jrs14855 said:
I have heard about this on hot rodded 320's. It would really require the 360 sump to take full advantage of the larger carb. Most of the hot rod engines are injected so this is not very common.
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Hmm... are the intake tubes not the same size? :) Seem to be on most models. The spider and sumps on most have the same part #? Just asking and interested. :)
 
Same or different flange?

I thought (maybe mistaken) that the sizes on the carbs are indicated by their number, like a 3 is 3", 4 is 4". So is an MA-4-5 bigger internally and still a 4" flange, or does the 4-5 mean something else like a 4.5"?
 
blaplante said:
I thought (maybe mistaken) that the sizes on the carbs are indicated by their number, like a 3 is 3", 4 is 4". So is an MA-4-5 bigger internally and still a 4" flange, or does the 4-5 mean something else like a 4.5"?
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Depends on your sump and/or your adapter...
 
tubes

Intake tubes on carbed 360's are the same diameter as the larger 320 tubes. Several different variations in tubes on 320's and same with injected 320's and 360's. Some of the 320's with large intake tubes are reduced to a smaller size at the sump. Never have figured that one out. Mahlon says the small tubes on a 320/160 hp probably cost a couple of hp.
 
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