We tested a 401 CID LS2 engine on a carburetor gained 19 lb-ft and 15 HP at 4200 RPM, averaging 13 lb-ft and 11 HP up to  5000 RPM, it also averaged 5 more HP and 4 more lb-ft of torque from 5700 – redline!

The engine had 11:1 compression, mildly ported stock LS2 heads(ported by Volcano Manifolds), a Lunati hydraulic roller cam, comp cams roller rocker arms, and an Edelbrock Victor Jr intake manifold.

Ignition was controlled by an MSD 60143 LS DIS Ignition Controller with the stock coils, cam and crank sensors.  MSD Spark Plug Wires were used.

The exhaust was Kooks long tube stainless headers with 1 7/8″ Primaries and 3″ collectors.  

The entire fuel and induction system can be purchased through Volcano Manifolds including the Intake Manifold w/Volcano System , and the MSD Ignition system, fuel system, and plumbing.

To Purchase Intake Manifold

To Purchase MSD LS Ignition Control

The graph below shows the two curves the performed the best and the lowest…in this case the baseline test being the lowest performance, and one of the Volcano Inserts being the best for this application.  The Volcano Inserts also smoothed out the dips in the curve and increase peak torque and HP ….


Just as with the EFI version of this engine, sometimes the Dormant Volcano comes alive and surprises you!  In this chart showing all 3 currently available Volcano Inserts and the baseline*, the Dormant Volcano outperformed the baseline and the two taller Volcano inserts, which is not what we expected and shows you how important it is to be able to change the Volcano insert in only ~5 minutes at the track or on the dyno to see what works best for your particular application.  The Dormant Volcano and the baseline are the only two visible in the chart above.  You can see how when you find the correct insert for your combination, it smooths out the curve and increases TQ and HP throughout most or all of the RPM range.  

More Results

*The baseline is an extremely thin nearly flush plug with no locking or aligning features, machined solely to mimic the factory manifold without any modifications to the plenum floor.