Water Pump Underdrive Pulley

Pulleys & Belts - Water Pump Underdrive Pulley
Pulleys & Belts - Water Pump Underdrive Pulley

Water Pump Underdrive Pulley

14 reviews
Regular price $69.99
  • In stock, ready to ship
  • Inventory on the way

Dyno testing our 5.5" underdrive pulley on a near stock L36 showed 3WHP gained at 6k rpm. In car testing shows only a 2 deg increase in operating temps over stock. Higher gains are possible depending on your engine combination. Pulleys are available in a high gloss black anodized finish.

  • 8% underdriven
  • dyno proven horsepower
  • lightweight design saves a pound of rotating mass
  • increases water pump life expectancy
  • better fuel economy

One size larger than stock belt recommended.

Does NOT fit HBody cars because of their front engine mount. Bonneville, Park Ave, & LaSabre.


Water pump pulley: 115 in/lbs.

Customer Reviews
4.9 Based on 14 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
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Filter Reviews:
  • serp belt work mint
  • IC cai base tune
  • 6000k
  • engine response
  • stack
  • weight difference
  • range
  • down pipe
  • size
  • pulley
Jason A.
United States United States

Worth every penny!

04 Impala SS 3.1 pulley double stack IC cai base tune with 3 in down pipe. Definite increase in engine response off idle, also in the 5000-6000k rpm range it seems to pull better (might just be me) but this bolt on is 100% worth the money. It’s amazing the weight difference when comparing the old pulley to this one. I jumped up a half size on my serp belt work mint! BUY IT!

Antone J.
United States United States

Underdrive pulley

it fit good an very light compared to the oem

Joshua T.

Easy first mod

Easy install for quick gain in hp I’d recommend a lower degree thermostat and make sure you order the proper belt size

Osiel J.

Pulley slaps right in a

Pulley slaps right in a lot lighter then OEM product. Noticed different idle and faster throttle response would definitely recommend one of these bad boys

David S.

Underdrive water pump pulley

Very light weight when compared to stock pulley! Only needed to go 1/2 inch bigger in belt size. Idle has improved as well as revs and slight pull when accelerating. Didn’t get 5*s because it had some couple jagged edges where the belt lays that needed to be ground down, but it a very nice item.

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