Don't have the biggest filter, but -
with my Amsoil 4510 I get better air flow and some whistle.
I do have the filter shielded from the engine compartment.
The temp at the intake horn went down ~ 20* - guess due to better flow...
After I "reworked" the firewall behind the park lights the intake temp dropped nearly 35* to just above outside temps and the temp at the intake horn is ~ 25* warmer.
Those temps are not pushing the engine. When my tranny gets rebuilt I'll push it to see what happens to the temps then.
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'93 D250 auto, 18.5cm w/30 psi, 366 spring w/1 turn clipped, power screw bottomed-backed off 2 turns, Ol Smokey's power pin, replaced limit washer-0.010, smoke screw fully out - not touching, 4" dp into 5" pipe to single 5" stack, 4510 w/4 1/2" intake and heat shield, grid heaters mia