Mopar Technical Articles
Mopar Project Cars
Mopar Events & Auto Shows
Mopar Car History
Mopar Wallpaper & Desktop Themes
Mopar Muscle Magazine Community
Subscribe to Mopar Muscle Magazine
Give a Gift
Create Your Own Cover
Edelbrock's Thunder Series AVS Carburet...
Dyno Test Results
2014 Mopar Event Schedule
1969 Plymouth Barracuda - Street Freaks Revisited
The Show Must Go On - Off The Line
Hot Parts - June 2016
Edelbrock's Thunder Series AVS Carburetor - Tweaking An Edelbrock AVS
Tuning For Horsepower And Fuel Economy- It Can Be Done
, Photography by
February 01, 2004
Rear Wheel Horsepower
Superflow Chassis Dyno
Tested At Westech
On the secondary side, we replaced the original 407 jets with a pair of 392s. On the primary side, the factory 413 jets were replaced with leaner 404s. With the jetting change, power went up to 325 at the wheel, while the average air/fuel ratio leaned out to 12.21:1. More power and less fuel-we like that.
On the secondary side, we replaced the original 407 jets with a pair of 392s. On the prima
Satisfied with the WOT mixture, we turned our attention to the part-throttle and cruise response. With the leaner jets, we now developed a lean condition at part-throttle.
Satisfied with the WOT mixture, we turned our attention to the part-throttle and cruise re
To fatten up the cruise mixture, while keeping the WOT setting unchanged, we needed a metering rod with the same power step diameter at the tip, while having a thinner part-throttle step higher up the rod. We settled on a 6547 rod, which measures .065 inch on the cruise step and .047 inch on the power step. The stock rods were 6847s, which measure .068 and .047 inch on the cruise and power steps, respectively.
To fatten up the cruise mixture, while keeping the WOT setting unchanged, we needed a mete
The rod change brought the cruise mixture to where it needed to be, showing a 13.5:1 air/fuel ratio. While it cruised cleanly, there was a lean hole when applying throttle from cruise to power, or tip-in.
The rod change brought the cruise mixture to where it needed to be, showing a 13.5:1 air/f
We figured that getting the rods to switch from the cruise to power position sooner would allow the mixture to fatten up a little sooner as tip-in throttle is applied. Changing the metering-rod springs will affect how early the rods will move from cruise to the power position. Metering-rod springs are rated by the vacuum level at which they will move the metering rods to the power step. Stiffer springs will lift the metering rods to the power position sooner. We used the silver springs, which move the rods to power mode at 8 inches of vacuum.
We figured that getting the rods to switch from the cruise to power position sooner would
With the power and part-throttle tuning done, the icing on the cake was setting the idle. With some careful adjustments using a vacuum gauge, we finally ended up with 11 inches of vacuum at a 750 rpm idle-not bad for a cam with 239/243-degrees duration at .050 and .537/.549-inch lift.
With the power and part-throttle tuning done, the icing on the cake was setting the idle.
2700 California St.
View Full Article
Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
User Submitted Content
Give a Gift
Create Your Own Cover
Mopar Muscle Magazine
, Source Interlink Media
All rights reserved.
MOPAR MUSCLE is licensed to use MOPAR, a trademark of Chrysler LLC, in the website domain name "www.MOPARMUSCLEMAGAZINE.COM". No other connection with Chrysler LLC is expressed or implied. The editorial opinions are those of MOPAR MUSCLE and do not necessarily represent the views of Chrysler LLC.