Want more power from your...
Want more power from your late-model Hemi? Indy Cylinder Head has a CNC program to port the 5.7 heads, with dyno proven results.
It's difficult to argue with the technological advancements that make Chrysler's new products like the Challenger and Charger fun to drive. Chrysler's late-model Hemi engine is a prime example of these advances in technology, with many features that older Mopar engines just didn't offer. From the factory the 5.7, 6.1, and now 6.4 liter Hemi engines come equipped with a roller camshaft, lightweight valve train components, and a sophisticated oil system to reduce crankcase windage. And like the first and second generation Hemis, the new Hemis benefit from impressive cylinder head flow numbers right from the factory.
Here at Mopar Muscle, we always knew the late-model Hemi engines would be a hit, as they very easily make big-block power and torque while remaining very economical and running great on pump gas. The aftermarket has also embraced the new Hemi, and it's now easier than ever to get more power from the engine in your new Challenger, Charger, Magnum or 300. Installing a third generation Hemi in an older Mopar has never been easier either with parts like the Mod-Man intake from Indy, ignition systems from MSD or FAST, oil pans from Milodon, and headers from TTI. Thanks to this aftermarket support we're seeing more and more late-model, modified Hemis not only in LX platform cars, but in older Mopar show cars and racecars as well.
The 5.7 engines are the most common of the late model version, and because they were installed in nearly every V-8 equipped late-model Mopar, including trucks, they are getting more and more abundant and inexpensive to buy. The 6.1 and 6.4 Hemis obviously offer greater displacement, and their cylinder heads do flow better from the factory than the 5.7 heads. Unfortunately they are also more expensive and hard to find due to the limited availability. Recognizing the performance potential of the 5.7 Hemi head, Indy Cylinder Head developed a CNC program to port these heads, resulting in impressive flow numbers.
Cylinder head flow is an important factor in any internal combustion engine, and the new Hemi is no exception. By CNC porting the 5.7 head and performing a multi-angle valve job, Indy improved the intake flow of these heads by more than 50 cfm throughout the .500 to .700 inch valve lift range where peak power is made, with significant flow improvements at lower lifts as well. On the exhaust side, flow was increased by 40 cfm from .500 to .700 lift, with noticeable flow increases at lower lifts.
We were invited to Indy's shop to dyno test a 6.1 Hemi with a set of CNC ported 5.7 Hemi cylinder heads. This was a cool dyno session, demonstrating the power a third-generation Hemi could make while remaining nearly stock. Indy's website advertises this same 6.1 Hemi with a factory SRT-8 camshaft, topped with CNC ported heads at 435 horsepower and 410 lb/ft of torque. You'll have to go to the website to see how much power this engine actually made, but we'll just say it easily exceeded the advertised rating.
While we were at Indy Cylinder Head we also got to check out a set of their CNC ported 5.7 castings up close, and were impressed by the quality of the port work on the heads. Chrysler's exceptional engineering, combined with Indy's modern computer-controlled machine work, has made building a powerful late-model Hemi engine more economical than ever. Indy sells the 6.1 engine we tested with un-ported heads for less than $7,000, and CNC porting is only a $600 upgrade. With power and torque numbers well above 400, it would be difficult to build a Mopar big-block or even small-block with similar power numbers for the cost.
Check out the flow and dyno numbers below and you'll agree, the new Hemi engine is potent for its size, and its light weight and smooth idle qualities make it an ideal sleeper engine for a late-model or classic Mopar. Indy's basic 6.1 is conservatively rated at 400 horsepower and 375 lb/ft of torque, but add Indy's CNC porting to the 5.7 Hemi cylinder heads and the third generation Hemi really comes alive, making well over the claimed 435 horsepower rating. Be sure to check out our website, moparmusclemagazine.com, for videos of this engine making pulls on Indy's dyno.
Indy Cylinder Head 5.7 Hemi Head flow before and after CNC Porting:
|Lift||CFM before||CFM after porting|
|Lift||CFM before||CFM after porting|
1 The 5.7 Hemi cylinder head...
1 The 5.7 Hemi cylinder head has smaller ports than the 6.1 and the new 6.4 head, but still has great flow potential. The 5.7 cylinder head is also more readily available and less expensive since the engine was produced in far greater numbers than the 6.1 or 6.4.
2 Even though the 5.7 Hemi...
2 Even though the 5.7 Hemi head has flow numbers comparable to ported big-block cylinder heads right out of the box, Indy's CNC porting cleans up the intake and exhaust ports, and the bowl area under the valves, resulting in a dramatic increase in flow.
3 The intake side of the...
3 The intake side of the cylinder head is where most engine builders concentrate, and Indy improved the 5.7 intake flow from a best of 273 cfm at .700 lift stock, to a healthy 327 cfm after CNC porting.
4 The exhaust port is also...
4 The exhaust port is also important when it comes to making horsepower and torque, and Indy's CNC porting increases exhaust flow from 180 cfm in a stock port to 221cfm after the port work.
5 We wanted to see how well...
5 We wanted to see how well a pair of these heads performed when placed in a non-factory type of condition. So, to step up the pressure on the heads, we installed them on a stock 6.1 liter short-block with a carbureted intake using dual 500 cfm Edelbrock carburetors. With our pair of CNC-ported 5.7 heads, and a Mod-Man dual-quad intake manifold, the 6.1/5.7 Hemi amalgamation made 465 horsepower and 423 lb/ft of torque. A stock 6.1 is rated at 425 horsepower, and 420 lb/ft of torque, installing the heads add roughly 40 horsepower, and 423 lb/ft of torque. We suspect that the head's improved flow now needs some additional camshaft to reach their full potential.
6 The Indy Mod-Man intake...
6 The Indy Mod-Man intake allows easy switching between single four-barrel, Six Pack, dual quad, and even a blower induction system by simply changing the top plate of the intake. We dyno'd this 6.1 Hemi in various configurations, so stay tuned for all the results in a future issue of Mopar Muscle.
7 Although our Hemi is carbureted...
7 Although our Hemi is carbureted in this configuration, we still needed to control the ignition. FAST offers ignition systems for the new Hemi, and we used it because it was already in the dyno cell. The FAST system can also run the fuel injection, but we bypassed those functions since our test engine was carbureted.
8 When this 6.1 fired up...
8 When this 6.1 fired up on the dyno, the idle was smooth and it had great throttle response-like a stock engine should. With the CNC ported 5.7 heads and a stock SRT-8 camshaft, this is a very docile combination that runs great on pump gas and easily makes big-block torque and horsepower.
9a Indy Cylinder Head sells...
9a Indy Cylinder Head sells this exact combination that we tested, claiming 435 horsepower and 410 lb/ft of torque.
9b During the testing we saw this engine easily beat these claims. By how much you ask? The dyno charts don't lie.