afco 3850 for the rear
3855m for the front .

afco recommended me there 125# springs

with a guesstimate of 1600 pounds on the rear

my car is 3375 with me ready to race

what size springs do other duster guys use,

The 125's will work well for you at that weight.

imo strange has been great on my car and some other cars i have helped set up for radials and offers free stiffer valving at no extra cost for cars over a 1000 hp if you run a slick shocks do not need to be as good

Did you do your home work and measure the length required for your car???? I would not just go with there recommended shock length, Take the time and measure.

We run Strange DA on the rear of the heads up car. They do have their Pro Mod valving in them too. Been great for us and we are handcuffed by running a very short shock because of the body style of the car.

As for spring rate you just need enough spring to hold the car up with the shock at ride height.

bought the afcos
duster 3375 new best 60ft 1.33 tb rpm4500
12.5 psi 29.5 x 10.5
hit 14 click from full stiffness
bump 9 click from full stiffness
I didn't even try other settings car pulled wheels 50ft

NOW on to the other issue jet changes didn't affect mph
131.66mph im losing 4-5mph due to something ? almost @ 1000ft it just wont pull more rpm it seems like it hits a wall

happy with the afcos

Hood scoop or no? Fuel pressure on big end? RPM where it is occuring? More info on the combo and whats going on up top will help.

no hood scoop, rock solid pressure 5.5 psi, isky 700# over the nose pressure on 276@.050 .630 lift.
1.33 sixty
1-2 7000rpm,
2-3 short shifted at 6300
mph still stays the same
more info coming

What carb and what needle and seats.. need more
info to help you

1.33 60
4.042 330
6.35 1/8th@ 106.25mph
10.07 1/4@ 131.66mph

hp innovation e 85 carb PLEASED with .130 seats

1050 dommy relative flat fuel curve entire pass of .077 thru .086 lambda with jetting changes never changed mph at the stripe of 131.66 every time?
timing locked every pass.
car has run previous 9.92 with home built QFT 1050/4150 better weather ? cant compare don't have the data
making pass at just before 1000ft it seems to stay stuck on 6700 rpm and cross at 6700