I have new 383 in my Duster. The motor is 9.6 to 1, 906 heads, solid 250 @ .50 108 lsa, victor 383, brawler 850, 2” Hedman fenderwell headers, Unilite distributor and MSD digital 6 box. The fuel comes from a pro comp black pump dead headed to a basic Holley regulator. When I got it together in March I took it to Beech Bend at it went 11.36/119 car weighs 3315 with me in it. COVID hit and it sat in the garage until June, then when I took it out it dropped to from 119 to 116-17, 20 degree temp increase so I thought maybe. I pulled the plugs (Autolite 85) and they look just like they did when I put them in (no color on anything-see picture). I started jetting at 76/84 4.5 PV went all the way to 94/94 6.5 PV nothing changed with the plugs. All runs were 6.5lbs fuel pressure and mid glass float level. I tested the PV and they all worked as they should.

From there I tested the fuel pump. I ran it for one minute through the regulator and it delivered almost 2 gallons. I ran a smaller sample from each side of the regulator and got 12 oz on each side in just under 6 seconds. From there, I thought that maybe I was losing voltage to the pump. I have it on a relay tied directly to the battery but my little alternator (40 amp) has trouble keeping up when I run my fan (33 amps). I scored a Power master alternator at a swap meet that puts out 85 amps at idle. I am seeing a significant increase in my voltage now, with everything I have turned on, it is still keeping the battery over 13 volts before when the fan was on it was barely showing 12 volts.

Down track the fuel pressure is staying consistent and my manifold vacuum is nearly zero so the PV should be supplying the extra fuel. Tonight was my first pass with the new alternator, I started back at 76/84 and moved to 82/90 and still nothing on plug color. The car actually slowed down from 116.11 to 115.27. I did try reducing fuel pressure down to 5.5lbs thinking it may actually pick up some volume. The weird part is also I do not feel the car nose over or feel like it quits pulling. I leave at 2500 and shift at 6400.

I am at a loss as to what to do or check now.