Edelbrock 70050 Instruction - page 6
1.2
Jet Map Information
Edelbrock engineering has conducted dyno testing with the Performer RPM system to provide jetting
maps for the three separate plates at different jetting levels. These jet combinations are supplied with
this system kit to enable you to vary your engine’s power output. On a typical mildly-modified 350 cubic-
inch engine, you can expect the following approximate power gains for each of the jetting levels:
Square-Flange Jet Map
Spread-Bore Jet Map
Dominator-Flange Jet Map
Jet Map Footnotes
The jet map above has footnotes that offer the following instructions and technical information.
1. Use 1 heatrange colder plugs.
2. Use 2 heatrange colder plugs.
3. Use 92 octane pump gasoline or better.
4. Use 110 octane race gasoline or better.
5. Single Plane manifold only. DO NOT use a dual plane manifold at this horsepower level.
6. Advanced tuning required. Suggested timing adjustment is just a guideline. Engine component
modifications may affect timing.
The dyno tests were conducted at Edelbrock using a mildly-modified 350 cubic-inch engine. Both dual-
plane and open-plenum intake manifolds were tested to ensure validity of jetting maps for each
horsepower setting. Modifications included Edelbrock intake manifolds, Edelbrock aluminum heads,
dyno headers, and improved ignition. We also used different grades of fuel and colder plugs during the
testing. All stated timing adjustments listed in jet maps is where the motor being tested worked best.
Final timing should be adjusted to achieve best power and/or MPH per application. See section “5.0
Ignition Timing and Nitrous” for more info on timing selection.
Any variation in jetting patterns other than what is listed above and engine damage could occur. Please
contact the Edelbrock Technical Department with any questions you have concerning jetting patterns
and their effects on engine performance.
Horsepower settings of 200 and 250 are for single plane manifolds only. In testing, we found that dual
plane manifolds have some distribution problems at these super high flowrates that could cause engine
damage. Please contact the Edelbrock Technical department with any questions you have concerning
jetting patterns and their effects on engine performance when using a dual plane manifold.
Approximate HP Gains
Nitrous Jet
Fuel Jet
Timing Adjustment
Footnotes
100
57
57
3°-5° Retard
1, 3
150
68
68
5°-7° Retard
1, 3
175
78
78
6°-8° Retard
1, 3
200
85
85
7°-9° Retard
2, 4, 5, 6
250
99
99
9°-11° Retard
2, 4, 5, 6
Approximate HP Gains
Nitrous Jet
Fuel Jet
Timing Adjustment
Footnotes
100
59
59
3°-5° Retard
1, 3
150
71
71
5°-7° Retard
1, 3
175
81
81
6°-8° Retard
1, 3
Approximate HP Gains
Nitrous Jet
Fuel Jet
Timing Adjustment
Footnotes
100
57
57
3°-5° Retard
1, 3
150
71
71
5°-7° Retard
1, 3
200
85
85
7°-9° Retard
2, 4, 5, 6
250
104
104
9°-11° Retard
2, 4, 5, 6