1981Regal said:
Oh okay so it's setup like a edelbrock 1407?
Pulled top
Rods are
73*47 for cold/winter weather
75*47 for warm/summer weather
Primary is 398
Secondary is 398
When I dyno'd I pulled low mid 13-13.6 AFR. With you increased CR ID run a 400-410 secondaries
I'm calibrated close to the 1406 and I can get some black smoke out the exhaust
With the cam/CR you have ID shoot for close 1406 calibration
Primary .098,
Secondary .095;
Metering Rods - .075 x .047; pick up following rods
73*47 #1456 (24) ref to 1406 chart)
73*42 #1455 (23)
73*37# 1454 (25)
A 73 rod is ~4% richer then a 75 rod same thing with 47 to 42 at each step. A 37 rod is 8% more then 47
If your worried pick up
70*47 #1452
70*42 #1450
70*37 #1449 (19, is ref on the 1406 chart)
I'd pick up a another pair of 098 jets(#1427) for secondaries 095 to 098 is 4% richer
The calibration are pretty drastic.. But remember you cutting 20% or 150cfm from the carb. The end result, 4% rich/lean is a big jump on a 600 vs 750
1407 is
Primary .113,
Secondary .107;
Metering Rods - .071 x .047;
Step-Up Spring - orange (5" Hg)
As for sizing with Edelbrock subtract 300 from the number 398 is a "98" 400 is "100"
Rods 75*47 is the biggest rod they make. The first number is your high vacuum fueling (cruise), 2nd number is your low vacuum fueling(power).
The stepup spring comes in 5-6 inHG ratings. That tells the rod when to swich between cruise/power part of the rod.
Higher the vaccum rating sooner the change happens.
As for example I cruise at 18-20inHG I run a 8" HG spring. It will bring more fuel in quicker then a 5" HG spring since I have to put more load/open carb more to reduce vacuum enough to lift the rods.
The goal is a "smooth" transition..
The only main thing different betweem the 500/600/750cfm performer series carbs are primary bore size. 500/600 are the same and are smaller then the 750cfm carbs.
Secondaries are all same size, and the 750cfm primaries are same diameter as the secondaries
As for ignition, it's not stock and fairly healthy.
I have, MSD 6A, with billet dis, and a blaster SS coil, 8.5mm super conductor wires AC delco R42TS plugs set at .060" gap.
So that winded explanation done... Id pickup the 3 .073 rods I mentioned and a second .098 jet for secondaries. Rods are ~$13.00 jets are ~$7.00 each