In recent years, Dodge has produced four different Hemi heads. Here is a brief description of each. In 2003, the 5.7 Hemi received the first, followed in 2005 by the 6.1 hemi design. In 2009 and 2011 respectively, the 5.7 Hemi Eagle and 6.4 Hemi Apache head appeared along with Variable Valve Timing (VVT) and the larger 392-inch engine. As the engines got larger, the heads improved with the help of larger valve sizes and improved ports. As cams got bigger, the beehive springs got more aggressive and capable of handling more lift. The current king is the Apache head that flows more than 340 cfm.
5.7 Hemi 2003–2008
The 5.7 hemi cylinder head can be found on Dodge trucks and non-SRT passenger cars, making it the most common head in the family. It has a 161cc intake port that flows between 250-280 cfm at 0.600 lift, depending on the flow bench. We've seen published numbers stating 265 cfm, and we've independently tested the stock pair off the '06 eBay Hemi from a Dodge Ram truck and saw 259 cfm. The intake valve is 2.00 inches and range from 4.8504.900 inches in length.
The exhaust port is a small square with a 50cc port volume and flows around 180 cfm at 0.600 lift. Independent testing saw 160 cfm through the port. The valve measures 1.55 inches in diameter and, like the intake valve, is roughly 4.850 inches long and has a solid stem.
5.7L Eagle 2009–Present
The Eagle Hemi cylinder head arrived in 2009 with VVT (variable valve timing) on non-SRT Dodge passenger cars and trucks. As with the early head, the Eagle uses rocker shafts and 1.65:1
ratio rockers, but there are big differences in the size and shape of the intake port and the rest of the valve train. The Eagle uses 2.05-inch intake and 1.55-inch exhaust valves that are not only larger, they are also longer than standard. The rocker support is taller, and the valve-guide support boss sits higher on the top side of the head, moving it out of the intake port. The Eagle uses a larger square port like the 6.1L that flows a massive 331 cfm right out of the box.
6.1 Hemi 2005–2010
The 6.1 Hemi head was the standard engine on all SRT-8–equipped passenger cars and trucks, until 2011. It uses a square intake port that measures around 188cc* and flows 321 cfm at 0.600 lift using a 2.08-inch valve. The D-shaped 57cc exhaust port flows 194 cfm at 0.600 lift using a 1.650-inch exhaust valve. The cam on the 6.1 Hemi is larger than the 5.7L version, making the beehive spring good enough to handle up to 0.580 lift. At 74cc, the open chamber is smaller than that on the 5.7L yet larger than that on the Eagle, making it a good head for a big-bore 5.7 swap (see the Step Up sidebar). Aside from the larger- diameter valves, the 6.1 Hemi valve train uses the same 1.65 ratio shaft rocker system and valve locations as the 5.7L Eagle head.
*Based on in-house measurements at Modern Muscle Performance.
6.4 Hemi Apache 2011–Present
This head first appeared on the 2011 SRT 6.4 Hemi Challengers, Chargers, and Jeeps. It uses the same rockers and bolt pattern as the 6.1L but steps up to 2.14-inch intake and 1.650-inchexhaust valves. The square intake ports are closing in on 2x2 inches and the flow is in the 340 cfm range. To fit the larger valves and improved port, the guide is moved outside the port so the heads will only fit a 6.4 Hemi engine or something with 4.06-inch plus bore and custom pistons with the correct valve reliefs.
For the budget guy who just wants to port the cylinder heads and change the cam, the 5.7L heads provide a small cross section and good port velocity. If you are modifying a late-model Charger or truck, these two mods and a good exhaust system, with headers, should pick up between 100 and 110 hp at the wheels.
Guys who want to try the 5.7L Eagle head will need to add a 0.075-inch head gasket to lower the compression to a reasonable 11.0:1. You will also need D-port headers, a 6.1L or Eagle intake, and the raised valve covers. With the right cam, this mod should get you up to 420 hp at the wheel from a stock 5.7L-equipped vehicle.
A better bet is to use the 6.1L head on the 5.7. You’ll need to use the thicker head gasket, the D-port headers, and the 6.1L intake (or can you use the Eagle intake). The heads will flow like the Eagle ports and you get the improved valve train, as well.
If you are thinking about the Apache heads for your 6.1L the only way to use them is on a custom build with large enough valve reliefs, or buy a 6.4L Hemi. The Apache head won’t work on a 5.7L.