Part III - The V8 Option - Chevy V-8 Swap into a Jeep CJ (or YJ)
May. 01, 2006
Part 3: Engine installation, startup, and final details.
OK, here we are, the real deal. This is the most exciting part of the project, the ACTUAL installation!
At this point, the chassis is prepared, the old engine is out, you have the new engine (and possibly transmission) and all your parts ready to go.
Installing the engine into the Jeep:
Trying to move the engine on the engine hoist yourself is difficult and dangerous, get a helper during the actual drop in of the engine. Also, pay attention to the load ratings on the boom of the hoist, weight could be come a safety issue! First get the engine on the hoist from the stand. If you have a fixed transmission placement (driveshaft length problems, or existing tranny position you want to use), you can drop in the engine only after the tranny is in place. For me it was much easier to mate the engine and transmission together first, and then mount them into the Jeep. From here, it’s is simply lowering the engine in place and bolting it in. You should have the skidplate in place first for the transmission to rest on something when the engine is first installed. The combination will NOT be balanced on the engine mounts only.
A few words about engine placement:
If you are choosing your engine placement on your own (instead of letting the mounts place the engine for you like I did), here are a few things to consider (you will have to decide for yourself what your priority is). Most Jeep engines have a natural tilt down at the back. If you decide to install the engine higher in the engine bay, this angle will get worse and you may have body clearance issues above the transmission, as well as worse front driveshaft angles. Higher should be no problem for clearance to the hood with most intake or carb options, but always check before welding mounts. The plus side of a higher engine position is more oil pan and exhaust clearance to driveshaft and front axle. Further forward gives a longer rear driveshaft (this could help with a 4 speed automatic which is longer), but there is less radiator clearance, worse weight balance, and the engine sits closer over the front axle pumpkin, which might cause other clearance issues. Also, having the engine so far forward may cause the shifters for transmission and transfer case to be forward of the floor holes. Finally, some people have mounted their engine with a bit of a “twist” (front is more to the left than the rear) to help with driveshaft clearance and other issues. With so many variables, you can understand now why I chose the M.O.R.E. mounts and was done with it.
Transmission to transfer case adaptor:
I wanted to “clock” my transfer case flat for more ground clearance, so the adaptor I chose had to have this feature of additional mounting positions. I looked first at Advance Adaptors and Novak which both have a long history and decent products so I have been told. Both Advance and Novak adaptors use cast aluminum adaptors of about 3.5” in length. I decided to buy the lower cost, all steel Rube Adaptor. When I received the Rube adaptor, the build quality was poor and the output shaft replacement had poor quality spline cuts. After having to send it back once for holes out of position, it still did not work (holes for Dana 300 didn’t line up with adaptor hole patter), I sent it back and received a refund. Rube adaptor was polite in dealing with me, and I did get a refund, but I would not recommend the product.
After much research and not wanting to have problems again, I chose JB Conversions adaptor. The most expensive of the bunch at almost $600 with shipping, but it is made of billet aluminum (not cast) and was only 1.5” long INCLUDING the clocking ring. It is beefy and everything mated perfectly to the transmission and transfer case. Highly recommended.
You will probably have to drill new holes for your transmission mount in your skidplate. After the engine is in place, line it up (make sure you check shifter side to side location first) and drill your new holes. Attach the transmission mount to the adaptor, not to the transmission. The transmission mounts are not nearly strong enough for this application, and I have seen them crack under normal use.
Exhaust (Three general choices):
No matter what choice you go with, you will almost certainly have to make (or have made) a custom exhaust. Find a local place willing to take the time to do it right. If they can do mandrel bending (no kink at the bends), that is a plus because without mandrel bending, the kink in the bends effectively reduces the airflow carrying capacity. Welding will most likely be required as well.
Exhaust option 1: Full dual exhaust
I had been planning a full dual exhaust from the beginning. There are companies out there, which make headers specifically for this swap into your Jeep. Headman is one I know of for sure. I had their headers, and they were well made, and fit properly, but with the clocked transfer case, there was little way to run the exhaust down the passenger side, so I sold the headers, and moved on.
Two into one exhaust:
In this option, the passenger side exhaust goes under the oil pan, meets up with the driver side into one pipe, and then out. This was my favorite option (at least for Jeeps which will drive on the trail and need proper ground clearance). Shorty headers, or “rams horn” style headers are both good choices because the output needs to be very tight to the engine. I went with 2.25” pipes from both passenger and drivers side, coming together into a single 3” pipe. Then into a 3” muffler, and out the back. The guy who did my exhaust did a great job of tucking everything in tight to the body. Problems you may experience: There is little clearance in the area of the oil filter and frame rail. I had to pinch the exhaust pipe in this area. Moving your brake-proportioning valve up near the booster (TJ style) will help this. The front driveshaft may be very close to the pipe going under the oil pan. If you have less than 4” of lift, you will have low clearance here. Just keep that pipe tucked close to the oil pan to help the clearance problem.
I like inner fenders because they keep water, mud and guck out of the engine compartment. If you are willing to loose the inner fenders, this may be a great option for you. BUT be aware that the exhaust going down the outside of the framerail will sit below the body mounts and be vulnerable to trail damage. Also Tire clearance may be an issue depending on your setup.
Part of the attraction to the V8 is the sound, so I chose a Flowmaster Super 40 muffler (3”in, 3” out). It sounds strong and loud, but not obnoxious or “sharp”. I was worried that a single out would sound not so good, but as compared to a full duals I have hear, the sound was almost the same.
My rear driveshaft length was perfect, I didn’t even have to have it shortened. The front was a disaster. I had to run a custom 2-piece front driveshaft with a pillow block to clear the transmission pan. Even with the stock 1.25” diameter front driveshaft, I could not clear the pan. Tom Woods driveshafts made an excellent solution (at cost of $525 not cheap). I know high angle driveline makes them too. This is not unheard of, but not common. Whether or not you will have to do something similar depends on your combination. I would have moved the engine over to the drivers side more, but then the exhaust would not have fit, and the shifters would not have lined up. For the record, I have 2.5” of spring lift, 1” of shackle lift, clocked Dana 300, and Dana 44 front axle. If you have this combo, you WILL have front driveshaft clearance issues. Your situation may not be this bad, but plan on having the length changed due to new driveline length no matter what.
Power Steering pump:
You can re-use your Jeep pump (because it was a GM part which Jeep used). If you buy a GM/Saginaw pump (like I did on Ebay for $50), it is likely to have a compression fitting, instead of the Jeep O-ring fitting at the pump pressure hose (depends on year, options, etc). I could have had a custom hose built, but instead I decided to make a half-breed hose. I cut off the original pressure hose just before the rubber section. Then the local tractor sales place made a custom hydraulic hose for me. The flare fit right into the pump, and on the other end, a heavy-duty compression fitting was used (the kind which uses the little crush ring around the metal tubing). Total cost was $22 and it works perfect.
Jeep CJ alternators were GM style alternators, so they should swap onto SBC alternator mounts without modification. But if you buy a new one, do yourself a favor and get a higher amp single wire alternator. The prices are pretty good if you look around. I got a chrome 100 amp, 1 wire alternator, with billet fan for $83 on Ebay.
Previously, I’ve explained how to have your existing radiator modified for SBC use (or that you can get a new radiator, which are made specifically for this swap). For cooling lines, you will probably have to use universal type. I prefer not to use the steel coil insert kind because the wires corrode over time. I bought corrugated stainless steel ones on Ebay for $22 each (cut to fit).
I first chose a super nice Holley throttle bracket thinking it was the perfect solution. As it turns out, the springs were WAAAY to stiff, and the design did not accommodate the Jeep throttle cable snap (as it was supposed to). Thankfully Summit returned my money in full. Eventually I chose a Spectre brand universal style with kickdown bracket. For $20 it worked perfect.
If you rebuild your engine, or have removed the distributor, make sure the timing is set right before proceeding. Do not assume that if the pointer is pointing to number 1 plug, that you are all set. You could do major damage if the engine is 180 degrees out (remember, the cylinder comes up 2 times for every one time the spark plug fires). If you need to, do a static timing like this: stick your finger in the number one cylinder hole. Rotate the engine manually (no plugs installed) and you should feel the pressure pushing your finger out, as the timing mark comes to zero on the balancer. Then set it to about 5 degrees, that will be a good start. My engine is running well at about 15 degrees.
I put a piece of tape covering the keyhole in the column with a note on it: FLUID FILL! This way I wouldn’t forget. You could also write a checklist. In any case, be sure to fill your engine oil, coolant, power steering fluid, transmission, transfer case, and fuel (if this applies to you). Check for leaks after you have filled, and before starting. I had a leak in my valve cover gaskets (because I had not tightened the bolts enough) after initial start.
Safety prep BEFORE starting this engine.
First go back and check all your connections. Pull on the hoses, tighten the bolts and fitting, and so on. This may take an hour or more, but better to find it now. Now get some rags and towels out, have extra fluids available for final fill, and also have a fire extinguisher handy. It helps to have a second person with you when you start the engine for the first time to look for issues, and be there for assistance. Wear your safety glasses. I also had some bolt cutters handy just in case I had to cut a battery cable in a hurry.
If you have a carburetor, here is your startup procedure: put a small amount of fuel (like a 2 liter soda pop cap full) directly into the carb, then crank the engine. Don’t do what I did and pump and pump after you’ve already dumped fuel in manually, you will flood it. With the engine cranking, it should take only about 10 seconds or less to fill the fuel line if you have a mechanical fuel pump. If after about 3-4 tries you don’t get any popping or starting, you will have to diagnose whether or not you are getting spark and fuel. DO NOT stick your face above the carb when cranking at any time, a backfire could seriously injure you. If you think the engine is flooded, follow this procedure: Let the engine sit for 10 minutes in a fresh air place (open the garage door), then put pedal to the floor, and crank. If you pump the gas pedal it will flood more, but if you don’t touch the gas pedal, not enough air gets in. By pushing the pedal all the way down, you open the butterfly valves full open and allow more air to mix with all the excess fuel to clear the flooding.
Once it is running, check IMMEDIATELY for the following:
I had two things fail the first two startups, and both were extremely dangerous. First there was a small fuel leak at the fuel pump due to a cheap Autozone bad flare fitting. The open headers ignited it, and my new engine was on FIRE! I quickly grabbed the extinguisher (you had it ready right?) and put out the fire. Second time starting, the engine was coming up to temp, and the upper radiator hose (under pressure) popped off of the water neck , spewing hot coolant 30 feet! I had just turned my face away from the engine when this happened. What I am saying is to pay attention and be careful! The first few times you run the engine, anything could happen.
Before you take the Jeep for a drive, let the engine get up to temperature, and keep looking for problems. Also properly bleed the power steering system, check your oil level, and do a final fill if you have an automatic transmission (cycle through gears, check in neutral, repeat). You don’t want to be 2 miles down the road with a break or leak. After you drive it, carefully flex the suspension (ramps, ravine, dirt pile, whatever) to check for clearances, make sure you’re not pulling on a fuel line or something. That’s it, go out and enjoy the power!
A few additional notes about this swap: Feel free to email me at
for questions or pictures you would like me to take for you. I received no free products or services from anyone when doing this swap. I cannot promise all of the information is 100% accurate, but I did check my facts as best as possible before writing it here. EVERY Jeep is different (even one right behind the other coming off the assembly line), so keep that in mind that what did work for someone else might not exactly be the best solution for you (and the other way around). These articles are my opinion based on my experience. Don’t send me hate mail if you don’t agree. Do all of this work at your OWN risk. I am not responsible if you don’t know what you are doing and you hurt yourself or anyone else in any way.
For anyone who thinks my bling machine never makes it offroad………. I’ll see you at Silver Lake Sand Dunes, and at the Badlands.