carb/cam help

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FrankenDuster74

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I have a 74 duster it was originally a slant six auto and I'm making it a 318 4 speed daily driver/ weekend test and tune car I have an 8 1/4rear for it I was told to run q 488 cam and a holley 600 I guess what I'm asking is does that sound like a decent set up and would I be able to get away with using a carb with vacuum secondaries or should I find a carb with mechanical secondaries oh my intake is a weiand dual plane thanks for all the help
 
FrankenDuster74 said:
I have a 74 duster it was originally a slant six auto and I'm making it a 318 4 speed daily driver/ weekend test and tune car I have an 8 1/4rear for it I was told to run q 488 cam and a holley 600 I guess what I'm asking is does that sound like a decent set up and would I be able to get away with using a carb with vacuum secondaries or should I find a carb with mechanical secondaries oh my intake is a weiand dual plane thanks for all the help
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i dont know about that cam,use vacume secondary better off on the street
 
mechanical secondaries are fine with a 4 speed.

where you run into problems are with automatics, then you might want vacuum secondaries for street use.

cams can affect vacuum and mess with your power brakes. if you have manual brakes, any cam within reason will be fine for you. and actually, at .484 lift or whatever it's not usually a problem even with power brakes.
 
That's a HUGE camshaft from a duration standpoint for a 318.

You better get the ignition timing squared away or you'll have tons of issues whichever carb you decide to run.

vac or DP, learn to tune it and either will work and most of the time a DP will kick the snot out of a VS carb.
 
crackedback said:
That's a HUGE camshaft from a duration standpoint for a 318.

You better get the ignition timing squared away or you'll have tons of issues whichever carb you decide to run.

vac or DP, learn to tune it and either will work and most of the time a DP will kick the snot out of a VS carb.
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what he said...big cam for 318
 
Crackedback is right. Unless you have a lot of compression, real good flowing heads and 4.10 or lower gears it's too much cam. Is your 318 stock compression and heads, or? What gears?
 
Yes stock heads and compression has dual plane intake and headers it has manual brakes so I should be ok using a vacuum secondary carb?
 
you should be good, i woulduse an xe 268 cam instead of that mopar cam.it's a good cam for a 318...
 
bad440 said:
you should be good, i woulduse an xe 268 cam instead of that mopar cam.it's a good cam for a 318...
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X2 on the XE 268 Comp cam. I'd use a vacuum secondary Holley on this combo being a cruiser/occasional T&T deal.
 
A point of clarification - a vacuum secondary carb has nothing to do with engine vacuum levels. The "vacuum" that opens the secondary plates is supplied by air moving through the primaries of the carb. Engine vacuum means nothing, and overcarbing can be a problem.
IMO - either the 600 vacuum secondary would be a good choice, as would the 650cfm Thunder AVS.
 
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