5.7 swap questions?

Welcome to the A-body 3G Hemi party!

Here are my opinions and a shameless plug or two :) so naturally, someone will have a different idea.

The sky is the limit in this kind of motor swap.

Since you are using an 04, you definitely should plan to replace the valve springs even if you decide not to change the cam at all. The 03 & 04 Hemi's had some spring breakage issues that haunt you at the worst time and could cost your dearly.

A cam is definitely a great addition to the 3G Hemi's. There are much better cams than the 6.1 cam to consider, especially if considering a blower in the future. We (www.InertiaMotorsports.com, a FABO sponsor ) , have them for $420 shipped to the lower 48. No matter where you get a cam, make sure and get the appropriate length push rods for your combination of cam & heads, or else you will hear that Hemi “tick” that annoys so many folks. While you are in there throw on a 6.1 oil pump just for cheap insurance.

Heads are available from us starting at $1375 (exchange) Many of the big hp 5.7’s run 6.1 heads for the added performance. That is an easy bolt-on for serious hp.

You might want to consider changing to a 6.1 intake that has been ported, especially if you go with ported heads (5.7 or 6.1).

Throttle bodies are a good addition, too. We offer CNC Ported TBs for $250 (exchange). Don't waste your money on a TB spacer, though.

The Keisler transmission kits seem to be good, though I have not dealt with one myself. Mine is going to run a TF727 and we have a cuda that will eventually run a viper 6 speed.

Since you are going w/ the OEM computer, you will want a tuner system, ours are priced at $375 shipped w/ the canned tunes from Diablo . Diablo is the best out there for dealing w/ the factory Mopar computer. It allows you to adjust some of the settings of the OEM maps. To really adjust things wildly for a big cam or blower, you will use a Diablo dealer to write a program specifically tailored to your changes via the tools data logging capability.

Adding headers is a big bonus. Right now, TTI seems to have the A-body market on them as well as bolt-in motor mounts, though we are working on our own solution. We hope to use SRT Jeep pieces and our own custom motor mounts for a much more budget friendly approach. We have seen big hp out of the factory SRT manifolds.

The Kenne Bell has a nice set up. Be aware though that the stock 5.7 is not going to last long above about 10lbs. Piston ring lands tend to break and destroy the motor soon after.

The shop I work in, has built more than 100 3G Hemi motors, many of which hold 3G Hemi records in ΒΌ mile and standing mile events, in various vehicles.

So what order would I say go for the best bank for the buck and in what order if you want to gradually improve your motor?


  1. Cam & tuner
  2. Headers
  3. heads
  4. 6.1 intake
  5. Throttle Body
  6. Forged motor
  7. Supercharger system

To see what others say about Inertia, check out this link.

Feel free to check out my own project in my signature. A near twin of my 5.7 motor dyno’ed at 435hp. With the Inertia cam, an XV carb intake and TTI headers, we expect that this motor will be slightly higher powered than the other motor.

Good luck with your project.