Chevy 350 Conversion

• 350 Engine - Do your shopping early and try to find an engine complete will all of the accessory brackets (alternator, power steering pump, AC, etc) that you will need. It can be difficult to track that "certain" bracket after the fact. Plan on spending anywhere from $50 to $5000+ for your new engine. If you are not confident in your ability to rebuild an engine or believe that they're unreliable, look for a "crate" engine. Sometimes they can be cheaper than rebuilding an old engine ... plus, you get a manufacturers warranty.
  
  
• 3 or 4 Core Conversion Radiator - You will definitely need a new radiator for your swap. AMC runs their radiator hoses on opposite sides than Chevy. Plus, you will likely want something that it designed to handle the heat that your Chevy will generate. Several companies are making conversion radiators that will bolt right into your Jeep but, plan on spending anywhere from $200 to $600.
  
  
• Transmission - Depending on how heavy your foot is on the GO Pedal, you may want to consider swapping in a stronger transmission now. One common swap is the T18 (or T18a) transmission. It is a beefy 4 speed that more than capable behind a 350. Of course, you may find that you don't NEED to swap yours out. For example, the T150 is a very stout tranny but, it only has 3 forward speeds with a not-so-low first gear. Even so, it is very common in earlier Jeeps (eg. CJs) and can be up to the challenge. The NV4500 is the ULTIMATE swap but, it may cause clearance problems, expensive adapters, or driveshaft length changes. Unfortunately, it is a fairly long tranny and difficult to fit into a CJ5. Prices will range from free, if you can use your existing tranny, to $2000 if you splurge for a new NV4500.
  
  
• Conversion Bellhousing, Bellhousing/Transfer Case Adapters - Do some research and determine what transmission and transfer case you will run with your new Chevy 350 conversion. I do not believe that a Chevy 350 will bolt directly up to any transmission available from Jeep factory; you will need to find out if you can do your conversion with a bolt-in adapter or conversion bellhousing. This part may be expensive depending on your drivetrain choices; plan on at least spending at least $150 with the potential approaching $450.
  
  
• Motor and Transmission Mounts - Don't forget to buy new mounts for everything. You will have the choice of boil-in or weld-in engine mounts; choose the one you feel best suits your needs. They each have their pros and cons but, both are up to the challenge and will work just fine. $150 should cover everything but, could be MUCH cheaper if you weld up your own mounts from rectangular tubing.
  
  
• Exhaust - Will you be running dual exhaust with your new swap? If so, you have a choice of fenderwell headers or running the exhaust out the back. If you choose the latter, don't forget to budget money for a muffler shop to bend your pipes. But, check around before you decide to go that route as some shop will refuse to touch it due to emissions reasons. Also, you have a choice between headers or exhaust manifolds. Plan on spending at least $250.
  
  
• Clutch, Forks, Pivots, Etc. - Will you be running a manual transmission? If so, you have the choice between a mechanical and hydraulic clutch. Decide now and you can better plan your budget and shopping list.

• Steering Rod to Exhaust Clearance
• Exhaust to Engine Mount Clearance
• Engine to Hood Clearance
• Engine Bellhousing to Front Drive Shaft Clearance
• Engine Distributor to Firewall Clearance
• Exhaust to Body Clearance
• Ignition and Alternator Wiring
• Properly Fitting Radiator Hoses
• Sufficient Engine Cooling

Once it was out, I posted a note on rec.autos.makers.jeep+willys to see if anyone was interested in an AMC 304 V8. I got a few replies back and ended up selling it to a person in Conyers, Georgia. While he looked around for a trucking company, I bolted the engine to a pallet and took it to a friend's shop to use his hi-low in order to be able to load it on a semi. American Freight was chosen by the purchaser and they picked it up on a Wednesday in Michigan and delivered it to Georgia on Friday of the same week! How's THAT for service?

I originally had a 1976 GMC pickup that I had been saving a while for its 350 engine. I sold the truck for $200 to my cousin and kept the engine to rebuild. Even though it was a two bolt block, I felt that it would meet my needs. Once the engine was torn down, it became apparent that the 80,000 miles had taken affect and some serious wear was noticeable. In fact, one of the lobes on the cam was completely worn off! The cam and crank were showing so much wear that I felt it would be cheaper to find a new (used) block rather than pay to have this one completely re-done.

Faced with a bad engine, I realized that this project was not going to be finished in a couple of weekends. So, I decided to do the job right and completely rebuild an engine from scratch. I had toyed with the idea of purchasing a crate motor. Yes, it's an option but, I wanted to do it MYSELF! Quality crate motors in the 325hp range started around $2500 range and only went up from there! I knew that I could buy the parts and install everything myself MUCH cheaper than buying an equivalent crate motor. So, I rolled up my sleeves and tried to find some patience to do it right ... the first time.

I am fortunate that my cousin has a lot of contacts where he lives. One of his friends had a number of 350 engines at the time waiting to be rebuilt and was looking for a two bolt engine. I was able to swap my worn two bolt block (plus $200) for a complete, running four bolt engine. All I had to do was tear down this "new" engine and send the block out to be hot tanked ($35) so I could properly paint it. He also had a set of balanced aluminum pistons (.030) w/ rods and a pair of heads that already had screw-in style rocker posts installed. Wanting to do the job right the first time, I bought the pistons and heads for only $250 and planned on sending out the block out to have it bored out 30-over so that I could take advantage of the larger pistons and get some serious horsepower!

Now, you didn't think it would be this easy did you? Of course not! Once the shop had a chance to take a look at the block, they noticed that it had already been bored out. I had two options, bore it out .060 (the maximum for a 350) or find another block. Since I had already paid for my 30-over pistons, I decided to find another block. And, as luck would have it, my cousin had an extra block that he was going to use for a pickup restoration (remember that pickup I sold?). His goal was to build a serious 350 for a street truck and gladly offered to swap blocks. That way, I could bore his .030 and he could bore mine .060 ... everyone's happy!

I had Foltz Enterprises in Mt. Pleasant, MI bore and hone my engine block ($96). In addition, I had them turn (rods .020 and mains .010) the crank ($85) so that I'd basically have all-new components. When it came back it looked like a brand new, unpainted block. All that was left was to apply a few coats of high temp Chevrolet engine orange paint to pretty it up.

We did some serious work on the existing heads including a full port and polish job using a Dremel tool to handle the grinding and the "pencil" attachment to allow us to reach up into the ports. We also went ahead and enlarged the oil drain areas in the heads to help maximize oil cycling through the engine. I purchased new valve seals and springs for the heads; however, since I had the heads apart, I went ahead and sent them to Foltz Enterprises to have new valves machined and installed.

It was finally reassembly time! The first step was to reinstall the crank so that my new flat top pistons could be dropped into their new home. After that the cam was slid in followed by a new double chain timing set and chrome timing cover. Next, I new oil pump and pickup was installed. Since I completely rebuilt the engine and threw the block into a hot tank, I wanted to make sure that it was be properly lubed. So, I installed a new oil pump and pickup. Last, by not least, a new oil pan was installed and painted to match the block. To help everything look nice, I purchased a set of ARP stainless steel bolts ($80) for the engine. I chose to use their 12-point heads since I like the way they look. However, they can be a pain to work with unless you have a full set of 1/4" 12 point sockets. Typically stainless steel is weaker that normal Grade 5 SAE hardware; however, due to ARP's special manufacturing processes, their stainless hardware actually exceeds Grade 8 strength! As this point, I was starting to get a little excited so, I laid the intake manifold, valve covers, and carb on the engine so that I could get an idea of what the finished product would look like ... NICE!

I opted to use the 350 bellhousing conversion kit from Four Wheel Drive Hardware (4WDH - http://www.4wd.com). It came complete with a new clutch fork, pilot busing, throwout bearing, and mounting hardware. As it turned out, the bellhousing that they offer is really a Lakewood safety bellhousing. This thing is beefy! It's designed to contain the clutch if it should explode for racing purposes ... I hope I don't have that problem. I also installed a brand new clutch disc, clutch pressure plate, and 168 tooth flywheel purchased from Four Wheel Drive Hardware. The Lakewood bellhousing came with about 24 bolts to mount it to the engine block and backing plate. I wasn't able to use all of them as there wasn't enough clearance for all the nuts; even so, this bellhousing is beefy and I seriously doubt if it will miss a couple of bolts. It's still mounted with twice as much hardware as most bellhousings. The directions that came with the bellhousing suggested checking the centering tolerances of the bellhousing. They went on to say that it's likely to be okay from the factory but, if the bellhousing is offset, it could prematurely wear the throwout bearing and pilot bushing. I mounted the bellhousing backplate, flywheel, and bellhousing so that I could verify that it was centered using a dial indicator. Lakewood states that the bellhousing should bee within .005" of center. Mine appeared to be .006". Since I don't think that I could drill out the locator pin holes and align it any closer, I left it. I really don't think it will but, I'm hoping that the extra thousandth of an inch doesn't cause a problem.

By now, I had finished the frontend rebuild and the POR-15 treatment so it was time to grab the cherry picker and get to work! I decided that the easiest way to mount the transmission and transfer case was to remove them from the vehicle, separate them, and then bolt them to the engine while it was still out of the vehicle. With everything bolted together, I finally ready to start the installation process. I purchased bolt-in 350 engine mounts ($140) from Four Wheel Drive Hardware and bolted the frame portion in to the existing mounting holes. Since my CJ had bolt-in mounts as OEM equipment, I opted against using the weld-in type. I slowly lowered the engine into the frame and aligned the engine mounts. Unfortunately, the tranny was no longer at it's original location. This isn't necessarily a problem; however, I didn't want to have new driveshafts manufactured for my installation.

I decided that the best bet would be to mount the transmission to the skid plate in its original location and modify the engine mounts. This meant that the engine mounts would no longer line up ... I even tried swapping the mounts on each side of the frame. But, nothing lined up. I ended up mounting them as directed by the installation instructions and, using the existing holes in the frame, I drilled new holes through each mount. Grade 8 hardware was used to tie these into the frame. Many people weld their mounts to the frame but, since I'll eventually be swapping in a different transmission (ie. SM465), I wanted to be able to easily relocate them in the future. As a side note, I had plenty of room around my distributor! I talked with many people that had to cut large holes in their firewall to provide sufficient clearance; however, I didn't have any problems at all! Maybe it has to do with my fiberglass body? To handle the escaping exhaust gases, I temporarily bolted on some turbo mufflers using "temporary" flexible patch pipe. It was ugly but, it worked.

Once the engine was bolted down, I worked out the wiring and plumbing. I used a top radiator hose from a 1976 pickup truck and had to walk the shelves of the local auto parts store to find something to work for the bottom hose. I used the alternator and power steering brackets that came from my 1976 Chevy step-side pickup and everything seemed to work out just fine. There were apparently two different mounting locations for the power steering pump: a lower one off the driver side head, and a much higher mounting one. Some people had warned against using the lower mounting brackets saying that it wouldn't fit; however, it seems to work just fine in my installation. Once everything was bolted on and wired, I used some plastic clips to plug the oiling holes in the rockers so that oil wouldn't spray everywhere when I fired up the motor.

The moment of truth came with a blink of an eye. Since the motor was primed before it was installed, all I had to do was turned over the engine a couple of times with the plugs removed. Once I was satisfied that everything was correct, I preloaded the rockers, installed the plugs and wires, and turned the key. Ahhh ... it was music to my ears! It was evident that the motor was too far advanced since there was an occasional backfire through the carb. A quick twist of the distributor smoothed things out and it began to purr. Once the valve train was properly adjusted, I bolted on the valve covers and air cleaner calling it complete! <grin> The only problem that I noticed was the operating temperature. Even with this little bit of running time, the engine temp quickly climbed to 220 degrees! Yeouch! I solved this problem by wrapping the headers in an insulation swap. After that, it was at a steady 180 degrees. Even so, I purchased a heat wrap to help protect the starter since the passenger side header was too close for my comfort.

After over four months, the time finally came to bolt the fenders and hood back on. I found a local shop the next morning and, a couple fo hours later, I had professionally bent dual exhaust!

If you're considering this Chevy 350 conversion for your own Jeep, drop me a line and I'll see what I can do to help you through the process. Good Luck!