Product Summary

Universal Fit, Double Pass Radiator Style, Aluminum

  • 31" radiator features one 1.25" end to match the water pump outlet and one 1.5" end to match the upper radiator inlet, with included hose adapter to LS engines
  • Double pass design lowers coolant temperatures 10-20 degrees with 2.25” core
  • Two-rows of 1” aluminum tubes cool better than 5 rows of traditional copper tubes
  • Hose adapter has an integrated streamlined 1/4" 90° hose barb fitting for the steam line
  • Features dual 12 inch diameter electric fans with shroud, 2-3/8 inch wide, S-blade style, 10 blades, 750 CFM maximum airflow

Comes as a Kit

Key Specs

Radiator StyleDouble Pass
Radiator Flow DirectionCrossflow
Material TypeAluminum
Inlet LocationUpper passenger side
Outlet LocationLower passenger side

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Speedway Motors 9100257 Details

If you've decided to add modern power to your ride using an LS series engine, this LS Swap Radiator Kit is the perfect way to protect your investment and ensure proper cooling system function.

We wanted to offer a solution for the budget-minded builder that also kept aesthetics in mind. Instead of an inline hose adapter with an NPT bung for you to plumb in your own fittings, which can look like junkyard parts hacked together and is susceptible to leaks, we created a unique LS Steam Vent Radiator Hose Adapter. This adapter makes quick work of several LS swap radiator hose issues with one simple piece. It features one 1.25" end to match the water pump outlet, one 1.5" end to match the upper radiator inlet, an integrated streamlined 1/4" 90° hose barb fitting for the steam line, and a black finish to blend in with radiator hoses. The combination of this adapter with one of our professional-quality aluminum racing radiators means your search for an affordable and effective LS conversion radiator solution is over.

LS Steam Vent Radiator Hose Adapter Features

  • 1.25" end - matches water pump outlet size
  • 1.50" end - matches upper radiator inlet size
  • Integrated 1/4" 90° hose barb fitting for a streamlined look
  • Black finish blends in with radiator hoses

This LS1 Swap Radiator Kit features our double-pass universal aluminum radiator. These high-performance radiators feature 100% all-aluminum construction. The furnace-brazed core increases durability compared to other radiators with epoxy-glued or crimped-gasket sealing methods. Two rows of 1-inch aluminum tubes allow this radiator to out-cool a similarly sized radiator with five rows of copper tubes. A rugged billet aluminum filler neck with screw-in bleed is also included.

This radiator is designed for Chevy applications with both water necks on the passenger side.

Universal Aluminum Radiator Features:

  • Passenger side upper inlet, 1.50"
  • Passenger side lower outlet, 1.75"
  • All-aluminum, furnace-brazed construction
  • No cheap epoxy glue or crimped in gaskets
  • Maximum amount of fins per inch allows greater heat transfer
  • Two rows of 1" aluminum tubes (out-cools five rows of copper)
  • Billet filler necks

Unlike the older SBC or BBC, the LS engine family features a thermostat that is located in the water pump housing. While this design allows for temperature and flow to be regulated before the coolant enters your engine, having the thermostat at a low point means that any air in the cooling system can easily get trapped in your engine. Air bubbles in cooling passages disrupt coolant flow, create hot-spots, and can cause overheating issues, pre-ignition, and detonation. None of these are things that your new (or used) LS will stand up to for very long without damage. Fortunately, there are steam ports in the heads that allow this trapped air to flow away from critical cooling locations to a high point outside of the cylinder heads. Since these engines utilize a closed pressurized cooling system, the steam tubes must be connected back into it at some point. Stock radiators in vehicles produced with LS engines feature a port to connect the steam lines to, and a direct-fit LS swap radiator with steam port provision is likely available for your ride - at a high price tag. Our kit allows you to spend less of your hard-earned cash on a cooling solution without sacrificing appearance under the hood.

Learn more about how radiators work and selecting the proper radiator for your vehicle by reading our tech article, Radiator Cooling Performance.

If your application does not require additional cooling efficiency of a double-pass radiator, we offer 91604056 which features a single pass radiator.


Round Chrome Radiator Pressure Cap, 15 Lbs:

  • Pressure caps for radiators featuring 15-pound capacity
  • Chrome finish
  • 2-3/8" O.D. of cap top
  • 2-1/4" I.D. of cap top
  • Will fit a standard radiator neck
  • Sealing surface (which sits inside the neck) is 1-1/2" O.D.
  • Cap sides are 7/16" tall
  • While this cap is chrome plated for durability, it may not meet standards of a premium, "show" quality finish


Aluminum Fan Shroud for 31 Inch Radiator, Dual Electric Fans

  • Designed to concentrate airflow to your cooling fan
  • Composed of high-quality aluminum, it is lightweight and easy to drill through for a custom fit
  • Comes complete with rubber flaps for higher speeds when airflow through the grille increases
  • Instruction sheet
  • Bolt-on installation
  • Shroud made of 16 gauge aluminum
  • Fits dual 11" or 12" fans
  • 8 rubber flaps
  • Measures 18-3/4" tall x 25-3/4" wide x 1/2"deep


Speedway Universal Electric Radiator Cooling Fan, 12 Inch

  • Speedway Motors universal fans provide efficient airflow
  • Computer-balanced blades, heavy-duty one-piece construction, and a complete mounting kit included
  • Provides the cooling power you need with reduced noise and vibration
  • Reversible, so they can be configured as pushers or pullers
  • 12 inch diameter
  • 2-3/8 inch wide
  • S-blade style
  • 10 blades
  • 750 CFM maximum airflow
  • 2 fans included


Fan/Shroud/Cooler Mounting Kit

  • Consists of 4 threaded plastic bolts 3/16" diameter and approx. 8-1/2" long
  • Includes 4 1/4" spacers, 8 thin washers, and 4 metal wingnuts
  • Works great for mounting your fan shroud, electric fan, or oil cooler directly to your radiator
  • 2 mounting kits included


Recommended Sizes for Common Applications:

**Please note** These are not direct-fit radiators, and will generally require some modification to the vehicle for proper fitment

1966-82 C3 Corvette - Varies by year, see below

  • 1966-68 - 28" Width
  • 1969-82 - 31" Width

1967-91 Chevy C/K Trucks - 31" Width

  • 1967-72 Chevy C10
  • 1973-87 Chevy Squarebody C10
  • 1969-91 Chevy K5 Blazer

1982-93 Chevy S-Series - 31" Width

  • 1982-93 Chevy S10
  • 1982-93 GMC S15
  • 1982-93 GMC Sonoma

1982-92 GM F-Body - 31" Width

  • 1982-92 Chevy Camaro
  • 1982-92 Pontiac Firebird

1982-88 GM G-Body - 31" Width

  • 1982-87 Buick Regal
  • 1982-87 Chevy El Camino
  • 1982-83 Chevy Malibu
  • 1982-88 Chevy Monte Carlo
  • 1982-87 GMC Caballero
  • 1982-88 Oldsmobile Cutlass Supreme
  • 1982-83 Oldsmobile Cutlass Cruiser
  • 1983 Pontiac LeMans (Canada Only)
  • 1982-86 Pontiac Bonneville
  • 1982-87 Pontiac Grand Prix

1979-93 Ford Mustang - 28" Width

1973-86 Jeep CJ - 24" Width

  • 1976-86 CJ-7
  • 1981-86 CJ-8 Scrambler

Direct-Fit Options:


  • 1966-70 Impala
  • 1966-67 Chevelle/Malibu


  • 1968-72 Chevelle/Malibu
  • 1970-77 Monte Carlo
  • 1974-77 Buick Regal
  • 1966-77 Olds Cutlass
  • 1966-77 Pontiac Grand Prix
  • 1968-77 Pontiac LeMans/GTO
  • 1972-79 Chevy Impala, Caprice, Bel Air, and Biscayne 
  • 1973-90 Chevy/GMC Truck


  • 1967-69 Camaro


  • 1970-81 Camaro
  • 1968-79 Nova

NOTE: Applications for reference only - measure your existing radiator for proper dimensions. Measurements listed are overall which includes radiator tanks.


Speedway Motors 9100257 Specifications

MFG. Part #9100257
BrandSpeedway Motors
Radiator StyleDouble Pass
Radiator Flow DirectionCrossflow
Material TypeAluminum
Inlet LocationUpper passenger side
Outlet LocationLower passenger side
Row Quantity2
Tube Size1.00"
Overall Width Range31.00" to 31.99"
Overall Width31"
Overall Height Range19.00" to 19.99"
Overall Height19"
Overall Thickness3.00"
Core Width Range26.00" to 26.99"
Core Width26.25"
Core Height Range18.00" to 18.99"
Core Height18.125"
Core Thickness2.25"
Cooling FanDual
Transmission CoolerNo
Shroud IncludedYes
Radiator Cap IncludedYes
Fan Diameter12 Inch
CFM Range700-799 CFM
Filler Neck Height1"
Inlet Size1.50
Blade MaterialPlastic
Sold in QuantityKit