The first complete 427 Warhawk built by World was readied to run in DTS Dyno cell # 3. This exciting event took place on March 22, 2007. Testing continued over the next few days.

The test mule combination consisted of a World Warhawk LS7X 9.24 deck block, Warhawk LS1X heads, Edelbrock intake, MSD ignition and AED 4150 and 4500 carbs. Dynatech built the 1.875” headers. A (very mild) Crane Cam and Moroso race pan were selected.

Here are some build specs. The heads were “as-cast” and out of the box. OE 1.7 rockers, Hardcore 7.80” pushrods and Hardcore 1.550” dual valve springs were used. Manley Severe Duty valves were selected, sized at 2.080” and 1.60”  in 64cc chambers.

Manley 4.125” forged pistons with 8cc reverse domes sat .003” down in each hole. With an Eagle forged crank of 4.00” stroke, compression was 11.15:1. Eagle was also the choice for the 6.125” long forged rods.

Seen here are the ATI balancer and OE timing cover. Beneath them are a Comp Cams double roller timing chain and OE oil pump. Bearings are Clevite and rings are from Total Seal.

The initial test session was run with an 870CFM carb and 91 octane pump gas. Timing proved to be best with a 26° total in the MSD Controller. Various jets were tried but proved optimum at 75/84. The power proved to be amazingly consistent over the 14 pulls made in the first session.

Click here to see the dyno sheets with an 870 and 1050 carburetors.

As tested with the 4500 AED Dominator

It’s important to remember the early phase of testing this represents. This is not the final configuration by any means, but it’s a good start after a long-delayed program. Future offerings of these parts may contain different components based on test results. Naturally, pricing has not yet been determined.

So what did we learn? We think we’ve got a winner here and we’re definitely going to build complete engines. Next week we’ll start our big LS7X head round of testing and we’ll load it up with cam. We will, however keep the same pistons and compression as they’ve been cut for 12° valve notches - and we know the hot set-up is pistons out of hole, but we’ll get there.

Warhawk will become another quality World engine with dyno testing and warranty just like the rest of complete engine line. Keep watching here!

April 10th Update:

Our test mule continues to take a pounding without breaking a sweat. After the previous tests, a more aggressive hydraulic roller cam was the only change to the previous combination. See the latest dyno sheets under the last test session sheets.

Even with increased duration and lift the cam was not a “monster”. We kept the 1.7 rockers, LS1X heads, same spring package and no changes to the piston tops. Remember - this is a 427 inch package. We’re going to test bigger displacements when the 9.8 deck gets here.

Conclusions so far?

It’s still perfectly happy with the 26° curve and PUMP GAS. In each test session the 4500 advanced exactly 12HP and 9LbFt over the 4150-but the cam change alone was good for a solid 36HP and 24 LbFt with each carb. Oh-can we call your attention to 515 LbFt @ 3500 RPM? We’re not done yet.

It’s really getting interesting now...

Watch here for the bad-boy LS7X head swap very soon.

April 27th update

Well, today is 4-27 and we have news on our 427 Warhawk. An exciting new event has caused us to alter the previously outlined course.

Ongoing development of the LS1X head has led to a port and polish program which produced 340/240 numbers. We’ll run it on the mule in a few weeks.

In the meantime the Boss said to order 14.0:1 pistons, a solid roller and build a new block for LS7X heads in a 427 “Drag” version. That’s now a parallel program and it will develop separately as it’s own “animal”.  

Remember, we got to 614 HP when we stopped the as-cast LS1X testing. We’re looking for even bigger numbers from this surprising cathedral head. In a short time, we’ll know more.

June 25th update

 To date we have completed the port and CNC program on our LS1X heads mentioned above. Today they went on the test mule engine and we found some interesting conclusions. The engine remains exactly as configured in the previous testing including cam spec.

See the dyno sheet here.

The obvious fact is that the engine improved 14HP over the as-cast, out of box LS1X head tests. From 5000RPM on up the ported heads show a steady HP increase. Below 5000RPM they give up some torque to the as-cast version but then steadily increase torque by 15LbFt at the very top.

Clearly they are deep breathers and work well with the .637”-.657” lift of this cam.

We view this data from the standpoint that our as-cast head really is an excellent design and value because the ported version did not exceed its performance by a great amount. Further, for a primarily street-driven vehicle the superior velocity generated in this design provides much-desired torque at lower engine speeds. Your car will feel really snappy at part-throttle application. We suspect an EFI version would slightly improve these traits but we’re not there yet. For now, think about a 628HP Z06 on the street instead of the 505HP OE version.