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<blockquote data-quote="shiftless" data-source="post: 74973" data-attributes="member: 1940"><p>Originally posted by JM:</p><p></p><p>This is a post from a previous board that I saved.</p><p></p><p>I've never tried these recommendations.</p><p></p><p>Dustins Car</p><p></p><p>I had a 75 CDV, stock weight, MT3 cam, K&N Filter w/Erson drop base filter case, 795cfm Edelbrock built Q-Jet for 1 ton Chevy truck, Accel built dristibutor, Fully ported Edelbrock Alum. intake, Flowmaster exaust, FlowKooler Water pump, and the below mentioned timing curve. Best mpg was 20 at 75mph, most of the time it was 18 @80-85mph. Around town, depending on the throttle angle 14-16mpg.</p><p></p><p></p><p>Advance curve recommendations</p><p></p><p>If you want to use premium unleaded gas use the combo that I have been using for years.</p><p>With the stock 8.5:1 compression use 10-12 degrees initial, one gold spring and one silver spring and turn the adjustable advance counter-clockwise 10 turns or until part throttle pinging is eliminated. That puts it at about 35 degrees total at very low RPM like 1800 rpm. I have tried using more vacuum advance but it detonates like crazy with the spring package described. If you use the stiffer springs in conjunction with more vacuum advance the car is real lazy at WOT. It takes more RPM to get the centrifugal advance to open up and delays throttle response big time. Using less initial timing can work but the car will not want to run well in colder weather. It leans out bad enough to backfire through the carb when trying to accelerate during cold engine operation.</p><p>I have tried every combination of weights, springs, vacuum and initial advance and have found the combination I described to be the best compromise between fuel economy (18-20 MPG at 2500RPM or 75MPH) and power (lots of bottom end grunt) at part throttle and full throttle. If you try and use lower octane fuel it will work well for part throttle only. At WOT it will ping lightly with 89 octane, never have run 87 octane in my car so don't know about that. I used the weights that came with the Crane kit due to their lighter weight, and besides the stock weights are usually toast by the time you get to them. They wear heavily around the spring posts. It was the Crane kit, but I think I used the Accel vacuum advance.</p></blockquote><p></p>
[QUOTE="shiftless, post: 74973, member: 1940"] Originally posted by JM: This is a post from a previous board that I saved. I've never tried these recommendations. Dustins Car I had a 75 CDV, stock weight, MT3 cam, K&N Filter w/Erson drop base filter case, 795cfm Edelbrock built Q-Jet for 1 ton Chevy truck, Accel built dristibutor, Fully ported Edelbrock Alum. intake, Flowmaster exaust, FlowKooler Water pump, and the below mentioned timing curve. Best mpg was 20 at 75mph, most of the time it was 18 @80-85mph. Around town, depending on the throttle angle 14-16mpg. Advance curve recommendations If you want to use premium unleaded gas use the combo that I have been using for years. With the stock 8.5:1 compression use 10-12 degrees initial, one gold spring and one silver spring and turn the adjustable advance counter-clockwise 10 turns or until part throttle pinging is eliminated. That puts it at about 35 degrees total at very low RPM like 1800 rpm. I have tried using more vacuum advance but it detonates like crazy with the spring package described. If you use the stiffer springs in conjunction with more vacuum advance the car is real lazy at WOT. It takes more RPM to get the centrifugal advance to open up and delays throttle response big time. Using less initial timing can work but the car will not want to run well in colder weather. It leans out bad enough to backfire through the carb when trying to accelerate during cold engine operation. I have tried every combination of weights, springs, vacuum and initial advance and have found the combination I described to be the best compromise between fuel economy (18-20 MPG at 2500RPM or 75MPH) and power (lots of bottom end grunt) at part throttle and full throttle. If you try and use lower octane fuel it will work well for part throttle only. At WOT it will ping lightly with 89 octane, never have run 87 octane in my car so don't know about that. I used the weights that came with the Crane kit due to their lighter weight, and besides the stock weights are usually toast by the time you get to them. They wear heavily around the spring posts. It was the Crane kit, but I think I used the Accel vacuum advance. [/QUOTE]
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