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If you have anything else to add please PM me and I will gladly add it, provided it is good advice/info.
Or, E-Mail Kolak for information on ordering parts of his.
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Quoted from Kolak.

Here's just what you need -- my "top four" list of torture tested performance mods that I offer for your ZJ V8:

There are four areas that yield good performance improvements on the ZJ V8:

Air intake -- The K&N FIPK replaces the entire factory air box, filter, and air tube. It comes with a metal heat shield to isolate the filter from the heat of the exhaust manifolds. It's worth an honest 13 horsepower gain, and is priced at $259.00.

ECU -- The Mopar Performance ECU replaces the stock computer with a completely reprogrammed unit. It features altered fuel and timing curves, transmission torque converter lockup points, and the speed limiter is raised to 130+ mph. It yields a 20 horsepower gain and is priced at $280.00. It comes with a certificate for $100.00 back from Mopar upon return of your old ECU to them. This is an awesome bang for the buck modification, since it only takes about 20 minutes to install. I recommend a 180 degree thermostat along with the ECU. This will allow the Jeep to run cooler, keeping you away from spark knock. Price for the Robert Shaw Gen II 180 degree thermostat is $15.00. This is an all stainless steel, very fast acting unit. I also include a new FelPro gasket.

Exhaust -- really good gains here -- 20 horsepower without headers, close to 40 with headers. Here's all the information:

For the ZJ V8, the optimal pipe diameter for the exhaust system is 3". The factory diameter is 2.25", and suffers from poor bends and crushed areas, especially in the Y pipe. The factory Y pipe can benefit enormously by one simple modification: Have your exhaust installer remove the crushed area that runs adjacent to the oil filter and replace it with a nice round pipe section. This will give you the vast majority of the gain of replacing the Y pipe completely, at a much lower cost.

If headers are something you're considering in the near future, you can delay replacing the Y pipe, since the headers replace it entirely. Let me know if you're interested in headers, since I carry some very high quality parts designed by Mike Leach and manufactured by Doug Thorley exhaust. That is the company that makes all the headers for Mopar Performance. The Mike Leach headers are triple chrome plated, with a lifetime warranty. They are constructed from 14 gauge tubing, with 1/2" laser cut flanges, the most robust in the industry. Price on the headers is $525.00. If you're not thinking of the headers, then you should have your exhaust shop fabricate a new Y pipe. If you haven't found a good exhaust shop yet, call a local speed shop in your area and ask for some recommendations. They always know who the local exhaust "guru" is.

For the remainder of the system, I recommend a high flow converter made by Car Sound, with 3" inlet and outlet, Flowmaster muffler (either the 50 SUV or the 70 series, depending on how aggressive you want it to sound), and mandrel bent 3" tailpipe manufactured by Kolak Performance. This is the best combination of components out there right now, and I've spent lots of time testing various combinations. The Car Sound converter is really well made, all stainless and fully seam welded. It flows over 450 cfm in the 3" configuration. I use the highest flowing converter they offer -- check out their web site at

Flowmaster mufflers are legendary for their unique sound. They utilize a patented system of internal baffles and chambers, rather than the packing that most performance mufflers use. This contributes to their longevity - since there is nothing to burn out - and to their sound quality. Both the 50 series SUV and the 70 series induce very low levels of interior resonance into the vehicle, so there's none of the RPM related moaning and droning you hear with some other mufflers. Both the 50 SUV and the 70 series have the same sound character, and flow about the same. The 70 series is the quieter of the two.

The Mike Leach tailpipe is a really nice piece. It is mandrel bent for a consistent internal volume, and uses the stock hanger.

The "Kolak Exhaust" as it's known to Jeepers worldwide, is priced as a package, including the Car Sound converter, Flowmaster muffler, and mandrel bent 3" tailpipe. Price with the 70 series muffler is $350.00, with the 50 SUV muffler, it's $335.00.

You might also want to check out some nice exhaust tips at These are some of the highest quality tips I've found, at reasonable prices. I particularly like their stainless steel tips, due to the way they keep their appearance much longer. For example, the SA3512 3" stainless steel angle cut tip has been my most popular, and is priced at $48.00.

Lastly, I'd recommend replacing your upstream oxygen sensor as part of replacing the exhaust system. This should be done every two years, and will make you new converter function much better, while contributing to performance and fuel economy. Price for a genuine Mopar sensor for your ZJ is $84.00.

Last up are ignition mods. This is aimed at being supportive of all your other mods. Here's all the information:

My recommendations for the 5.2/5.9 ZJ ignition system are designed to improve idle quality and throttle response, and to improve and maximize current transfer. This really helps support other modifications. Here's what I recommend:

Magnecor KV85 ignition wires
MSD high output replacement coil
Heavy duty US made brass terminal distributor cap with rotor
Autolite platinum plugs (one heat range colder than stock)

Price for the kit is $230.00

Please take some time to read the information about plug wires on Magnecor's web site at Their wires are the finest I've found - incredibly flexible due to their pure silicone construction, and almost impossible to scorch or burn. Magnecor makes wires for many of the NASCAR teams, and their current transfer capability is amazing.

The MSD high output coil has fully 1/3 more output than the factory coil, and this really works well with the Magnecor wires. It's a direct replacement, and is easy to install. With the coil and wires, you can open up the plug gaps an additional .005 for a bigger spark. The colder plugs provide better detonation resistance.


Another Source
When dealing with the Magnum Motor, the best ways to start modifying the engine for more output, is to begin with the intake. What good does it do you if you start with the exhaust when you're not putting any more into the intake than you were before. You'll maximize your exhaust gains if you begin with the intake restrictions. The best place to start in the intake is with K&N FIPK system. This system by itself, will add a minimum of ten rear wheel on horsepower on a 360. We do all dyno testing with the FIPK. the Shaker hood is another fine option for the intake system.

That brings us to the throttle body. Choosing a throttle body can drastically affect the performance of the Magnum Motor. We offer for different millimeter sizes depending upon what is being built. The 48 mm, which is for the V6 Motors, the 50 mm which is for stock or mildly built V-8's, the 52 mm, which is for heads and cam combos (or supercharged/ nitrous), and finally the 55x52mm and the 58 mm, which are for maximum built motors. The manifold of choice for these combos is the M-1 Manifold (2bbl). This manifold can produce great numbers of torque and horsepower without doing exhaust mods.

Continuing on the intake, the next decision would be to change the camshaft or change to 1.7 roller rockers. If you choose not to change the camshaft, then install the 1.7 roller rockers. This does three things, it reduces friction, it adds lift, and it adds duration. This makes your stock camshaft appear to be bigger to the motor. By staying with a stock and camshaft, your torque band will be higher. with these modifications on a bone stock 360 R/T, average ET's will be in the mid fourteen second range. Keep in mind, that is with no exhaust mods whatsoever.

The next area to go to would be to improve the ignition system. What this does, is completely burn the mixture in the combustion chamber for maximum power. Both of these modifications to the intake and to the ignition system free up power and gas mileage at the same time. The only limiting factor to gas mileage is keeping your foot out of your newfound power. We use MSD and Crane ignition systems in the shop. There are many more available than just these, but that's what we choose to run here on the truck's.

The Magnum Motors use a Inlet Temp Sensor, to add timing or pull out timing depending upon atmospheric conditions. The nature of this sensor mounted in the intake manifold, heats up the sensor giving it a false reading of the actual ambient temperature that is going into the motor. By relocating the sensor to a colder location, the throttle response will increase. Typically, the ideal location for this sensor is to mount it into the FIPK. By doing this, you'll reduce its reading from 180 degrees to approximately 90 degrees. The stock thermostat Magnum Motor is 195 degrees. This needs to be changed to a 180 degree thermostat. Do not run the 160 degree thermostat, this will throw a code in the PCM for running too cold for too long . The second thing it does, is cause the truck to lay down in third gear by adding too much fuel. There are a lot of people running at 160 degree thermostats and assume that their truck is running fine. They have no idea that the truck could be running quicker. As I said, this is a starting point. You can use these items to build a stronger motor later on.

Once these items are improved upon, then you can go on to modifying the exhaust and PCM. All of these modifications above do not need an after-market PCM to run correctly. Dodge PCM's will correct performance (within a window) to maximize power and efficiency from these modifications.

Building the 318

Other Performance Options to Consider:

Turbo City High Flow Throttle Body
The Fastman High Flow Throttle Body
Turbo City Dual Air Tube Intake
Airaid Poweraid TBS Throttle Body Spacer
Mopar Performance V8 Single Plane MPI Intake Manifold
Crane PowerMax Camshaft
Mopar Performance Hydraulic Roller Lifters
Harland Sharp Roller Rockers
Edelbrock Performance Headers
MagnaFlow High Flow Catalytic Converter
MSD 8.5mm Super Conductor Spark Plug Wire Set
Champion Iridium Spark Plugs
ACCEL Mopar Remote Super Coil
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