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overdriven vs underdriven blower jetting

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overdriven vs underdriven blower jetting

Old 07-05-2016, 11:47 PM
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Default overdriven vs underdriven blower jetting

I have a 500ci bbc with an 8/71 blower and twin 750cfm holleys on it. The motors has amkt steel crank and rods so i wanted to swap the pulleys and overdrive it from 15% under to 15% over... only thing is, there are no dynos here in colombia to tune it on.
You think the jetting will need to be changed or should it be ok as is? Thx for any feedback, rm

btw its in a 48 anglia
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Old 07-06-2016, 06:36 AM
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I don't know the answer Ratman but post a picture of that bad boy, always liked those.
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Old 07-06-2016, 04:01 PM
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Originally Posted by iliveonanisland
I have a 500ci bbc with an 8/71 blower and twin 750cfm holleys on it. The motors has amkt steel crank and rods so i wanted to swap the pulleys and overdrive it from 15% under to 15% over... only thing is, there are no dynos here in colombia to tune it on.
You think the jetting will need to be changed or should it be ok as is? Thx for any feedback, rm

btw its in a 48 anglia
Thats a big jump in drive ratio. How much boost were you seeing, and how much are you hoping to get?
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Old 07-06-2016, 04:53 PM
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I smell aluminum. Where you at for jetting and timing. I'm no expert by any means however depending on where your at with the two I'd bring the timing back a couple degrees and up your jet size in your secondaries and don't leave it pinned for any for any real length of time until you feel comfortable. Do you have o2 sensors? A little risky without but if you do keep whipping the throttles after you pin it to help bring EGT's down.

Last edited by getrdunn; 07-06-2016 at 05:10 PM.
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