There's never such a thing as too much power when it comes to trailing in your Jeep. You can always use more horsepower, and even more important, more torque, to get you over that next boulder mud bog.
Throughout the Jeep's long history, from the CJ to the JK, power has usually come from a four or six cylinder engine. Few have had a V8 option, the height of which being in the CJ series when you could get an AMC 304, or a rare 360. Those were the days. All you had to do was check the right box when you ordered, and your new Jeep came fully equipped with a V8 straight off the assembly line.
But what if you need more power in the Jeep you have now?
Jeep CJ Engine Swap for V8For a CJ, it's not too hard. Folks have been doing it for so long now that there are various parts available to do it yourself and make things a bit easier. Today the popular swap is a Chevy 350. Typically an earlier block (meaning, no LT1 with the distributor off the front, or anything exotic). If you're not dropping in a used engine, you'll most likely be using a GM crate 350.
Of course, many other V8 engines have been used, but they're not as common. We'll be using the 350 as an example today.
Besides the engine, there are many other parts that are incorporated into swapping the engine, and making your vehicle a daily driver. The following is a list of other components you'll need before you begin the Jeep CJ engine swap.
Jeep V8 Bellhousings
If you want to keep your factory transmission, you need a bell housing to adapt from the 350 to the transmission.
One example would be Advance Adapters Chevy V8 to Jeep AX5 Bellhousing Adapter Kit (Part AA-712565V).
This works with the AX5 transmissions.
Advanced Adapters also makes a bellhousing for SR4, T-4, T-5, T-150 and T-176 transmissions (Part AA-712548).
If you're running a NV3550 5 speed, you need the bell housing adapter (Part AA-712591).
A T18 or T98 transmission can use an adapter to match the engine with the trans, (Part AA-712516).
Swapping the bell housing can also mean you need to swap or replace the throw-out bearing, fork, boot, and release arm spring. Sometimes you need to change the clutch master or slave cylinder as well.
You might also need a new clutch, and a flywheel, such as Advance Adapter's GM-Chevy 153 Tooth Steel Flywheel (Part AA-CF700170).
Jeep V8 Engine Mounts
Typically the engine mounts need to be replaced and redone. Advanced Adapters makes a kit to do this, with Part AA-713007.
If you want to make your own mounts, but need the plates for a 350, Mountain Offroad Enterprises makes some Universal Bomb Proof Motor Mounts, Part MOR-CB100.
With the bell housing and the motor mounts in place, you can at least work out getting the engine in the engine bay from a basic standpoint. Once you work out that the transmission parts and the clutch works and shifts properly, you can move on to other facets of the conversion.
Jeep V8 Headers
You will need some way to hook up the exhaust, so some kind of header is in order. Because of the design of a Chevy block, tight headers are commonly called "Shortys." They hug close to the block, and can fit well into tight spaces, often a popular choice with Street Rods.
Advanced Adapters makes their own Chevy 350 shorty headers, Part AA-717011. They also make a pair that work outside the frame rail, Part AA-717038. Those almost give your Jeep the 1960's "Gasser" style dragstrip look.
Jeep V8 Engine Cooling
Chevy engines are known to put out some heat. Your stock radiator probably won't be able to handle the extra work, and a good replacement is a good idea, along with an electric fan.
Once again, Advanced Adapters offers an aluminum radiator to keep your new engine cool, Part AA-716692-AA.
If you're running an automatic transmission, you can use part AA-716690-AA, if you're not already running a transmission cooler.
Be Cool also makes some aluminum radiators with electric fans sold as a kit. A good choice would be their BC-80030. It includes an Aluminum Radiator, a 16" High-Torque Fan, the Fan Mounting Brackets, a Recovery Tank, a Radiator Cap, and hardware (electrical and mechanical) to install them. If you just need an electric fan, Flex-A-Lite makes several different size and shaped fans, so they're quite versatile to fit your modifications.
Of course, if you want to bypass some of the mixing and matching with various parts, you can get an Advanced Adapters complete Jeep conversion kit, such as Part AA-CJ001, which has many of the parts you need in one box.
So far, we've only covered the big items. There are a multitude of different parts and ways to execute a Jeep CJ engine swap. These choices here exclude swapping the transmission from stock (another option) or the transfer case. If you've ever swapped an engine before, you know there's countless hours of rewiring, hooking up the cooling hoses, the fuel line, fan belts, and a host of a hundred other minor bolts, nuts, odds and ends.
But from a broad overview, you can see that there're some companies manufacturing some great products to make the job a little easier, so you don't have to fabricate everything on your own.
If you decide to do a Jeep CJ engine swap, make a list, make a plan, and get as many parts as you can ahead of time. Having a couple of Jeep friends over for the weekend doesn't hurt either.