Build a Twin Turbo Big Block Chevy 502

Do you need 1400 horsepower and want it to run on E-85 fuel? Just grab 2 turbochargers off of a 3.8 Buick Grand National, and you can achieve this goal. The single turbo from the 231 cubic inch V6 is perfect when you put one on each side of a 502 cubic inch monster.

Steps

  1. Buy a 502 crate motor 8.75:1 compression ratio. Re-clearance the rotation assembly - extra clearance in the bearings for additional crank flex, and open up the ring gaps for the additional heat of the turbocharger.
  2. Learn how to read a turbo map, decide what your horsepower goal is, and buy the correct turbos. For an old school 800hp setup - a pair of T04B V1/V2 compressors, P trim turbine with about a 1.2A/R is a good start. For a more modern setup, a pair of GT4094's would be a powerful combo with low RPM spool up.
  3. Spend the money on your fuel system to keep up with the horsepower and boost levels. A boost referenced FPR is a must. I would use either a Racepumps mechanical pump, Aeromotive, Holley Performance Products or similar. Blow through carb, fuel injection, will both work. CSU makes a nice Blowthrough carb setup.
  4. Tune it fat to start, and with low boost. Keep the timing low to avoid detonation. Tune it for whatever fuel you will be running most of the time. A wideband 02 monitor is a must.
  5. Enjoy...

Tips

  • Always use fresh fuel since fresh E-85 is 108 octane.
  • If you are not sure or have questions, check online forums for advice or if you know somebody with a turbo setup ask them for their opinions.
  • Never put something together you are not 100% sure is correct. This could lead to more expenses and a loss of time.

Warnings

  • Be prepared for significant power gains. If you have never driven a car/truck with this amount of power don't go out your first time and floor it.
  • Tire wear can be a real problem if you are running the Harmon Systems 502 twin-turbo system.

Related Articles

You may like