Staff member


I have a 540 with 360 cc Brodix heads. I do not beleive you can go too big with a blower. Down deep grunt is right there. I also run a 270/265 @ .050 solid roller on 114 lobe centers.
I run a 8-71 but would recommend a 10-71 instead to slow the blower down. I run 12% overdrive so bottom end grunt. My headers are 2 inch to 3 inch exhuast and feel a large tube would help but it would not fit the chassie.
I have extensively reworked 850 double pumpers with intake referenced power valves on the primary side. I added an extra circuit or jetted the tranfer ports for cruise. The idle can be set to whatever the motor likes for quality idle, then the tranfer ports pick up the cruise mixture 2000-3200 and I run lean 17-1 or so and the motor loves it, runs smooth, clean and gives great gas mileage. The main jets come in around 3300-3500 and they again are jetted richer but not too rich. I do tune with a wide band.
I run 24 degrees initial, 12 degrees mechanical all in by 3000 and 16 vacuum but that is not always used. If I am cruising 60-80 or 90 the vacuuma advance is full on for 52 degrees but if I feel like romping I flip a switch that opens a relay and I then feed intake vacuum to the vacuum advance and any advance is quickly switched to pressure in the vacuum advance and timing is backed off.
It works for me, the car will pull 308 gears and .68 overdrive right down to 1200 rpm in high and pull away smoothly. It doesn't overheat, load up and the plugs usually look white after a trip.
I am happy with the combination but if I had to do it again I would use the 10-71 but the rest I would leave alone.