It all started as a bit of a lark really. I was helping my son-in-law John with an oil leakage problem on his new toy a few years ago, an older CJ5 Jeep. Looking at the engine compartment, I mentioned that what we really should do is just give up on the straight six cylinder and put a small block Chevy in it. Nothing much came of it at the time. We did what we could for the oil leak, but the carburetor on it was worn out as were the piston rings. The cloud of oil smoke coming out of the valve cover filler hole was evidence to that fact. The engine either needed a complete rebuild which from certain witness marks appeared to have already been done at least once in its life or it needed to be replaced. Jump forward a couple of years and we talked again about what could be done engine wise for the Jeep. We originally talked about finding another suitable 6 cylinder engine to rebuild and then swap the refresh for the worn-out and call it good. Then we moved as every hot rodder does to something a little more fun. I went back to my suggestion of a small block Chevy motor and now I had the perfect candidate sitting on an engine stand at home. The Monza had come to us with a, well what was supposed to be a .030 over Chevy 350 “roller motor”. Now let me explain some of the terminology in that description. “.030 over” would mean that the cylinders had been cut 30 thousandths of an inch larger in size and doing the math should result in a new engine size of 355 cubic inches. “Roller Motor” in drag racing parlance means that the engine is equipped with a roller type camshaft and roller lifters. These items normally add substantial power to an engine as the valves can be lifted higher and longer. Modern factory hi-performance cars over the last 12-15 years have used this roller technology. Well, as it sometimes goes, the engine wasn’t exactly what we were told it was. It turned out that the engine was actually cut .060 over making it a 358 cubic inch engine and it didn’t have the roller camshaft and lifters. We were disappointed of course but the engine had served its purpose for us and had been replaced with a fresh power unit.
John agreed that this was the route we would take and on a visit in the spring, I loaded up the Jeep and brought it to Virginia from Florida. I started out the initial work by getting the block, rods and crankshaft over to my machinist friend, Chester Houghtaling. If you ever need precise, on the button machine work, a racing engine or just a rebuilt engine for your favorite ride, he’s the guy to see. (Contact me for his contact information) Right off the bat we had a problem, the crankshaft was junk, shot, done – finished. We had to find another one and something on the cheap to keep the project within the budget. It took a few weeks but we finally something that would work for us. It cleaned up with just a polishing so we were able to use standard sized bearings but it did have to be balanced to match our rod/piston combination. Next on the list was the top of the engine. I had already sold the Vortec heads that came on the engine along with the racing intake manifold. I didn’t have a carburetor either. I was also going to need things like a pulley for the water pump and another one for the power steering pump. We also needed an adapter to connect the Chevrolet engine to the Chrysler transmission that Jeep had installed at the factory. I needed a new radiator to match the Chevy engine, the radiator hoses and an electric fan for cooling as I did not want to mess with an engine mounted fan. We also needed a method of getting rid of the exhaust from the engine. The parts list became almost endless. I scored parts from Chester for a few items, RacingJunk.com for some and most everything else save for a few pieces I had on hand to toss at it came from catalogs or local parts stores.
Where we ended up was with a 358 cubic inch engine that might be a touch larger than that as we had the cylinders honed to clean them up. We used flat top rebuild type pistons with oversized rings that I hand cut to help keep the compression up, stock factory rods equipped with ARP bolts to keep the big-end together and another 350 crankshaft that was balanced to match them. The heads were mid-80’s units with a new valve job that measured 76cc to get the compression where we could run regular fuel. The camshaft is a mild hydraulic performance cam that is maybe a touch better that the old 350/350hp camshaft from Chevrolet. The rest of the valve train was stock 80’s stuff, as are the valve covers. The oil pan came from some previous project but fit perfectly and it covers a new Melling oil pump and pickup. On the initial fire-up we were looking at a nice 60 pounds of oil pressure using 10w-30 weight oil. With some heat in the oil we should be around 42-45 pounds – again perfect. The intake manifold is a mid-60’s Edlebrock dual plane unit that is fitted with a completely rebuilt and reworked Holley 650 CFM carburetor. Our first shot at the ignition was a Pertronix unit – later on we will tell you why to never, ever purchase one of their parts – but our second shot was a fantastic HEI unit, and more on that one later too.
With the engine built, it was time to address the Jeep and its 6 cylinder engine. One of the things that we wanted to do was to get rid of this engine. Now, I do have a local trash recycling facility that allows us to drop things like engine blocks and such, but you do have to make sure it is clear of any oil or coolant. You also have to have some method of getting it off the back of your truck and into the metal dumpster that is about 4-5 foot from your truck. I took a chance on the easy option here and ran an ad in Craigslist for the 6 cylinder engine. A couple of hundred for a complete, rebuildable engine that you could hear start up and run. I was shocked that it only took two days for someone to show up and take a look at it. They bought it on a Friday and I promised them that they could pick it up Monday afternoon, which meant I spent a good part of that weekend snatching the engine out of a Jeep.
With the engine gone, I took a little bit of time and tried to clean up the firewall and chassis area some. I say some because after a number of cans of foamy engine cleaner it really didn’t look like I was making much progress. Anyway, I wiped things down with some heavy duty degreaser, sprayed off the mess and let it dry. The first order of business was fitting the new adapter plate from Advance Adapters to the Chrysler transmission. Ha-ha, what fun we had with this one. The instructions are clear but there were several areas due to a lack of firewall clearance that made it more than difficult to mount the adapter and get it bolted up cleanly. I finally managed it but what I thought would be a 15-20 minute job turned into something that took several hours. I had to take the adapter off more than a few times to just slightly open a hole here and there to allow the bolt that they supplied to actually fit. There is also an adapter for the torque convertor that only goes on one way and with four bolt holes that have to be lined up perfectly, the challenge was that at any given point 3 of the 4 would but not that 4th bolt. But as you try each available combination you finally get it right and all 4 bolts fit the way they should.
Next up was actually installing the fresh engine. This is where I would love to say it fell into place, I bolted it up and everything was done. Nope. I struggled getting the back of the engine to even line up correctly with the adapter plate and when I finally got them mated, getting them bolted together was an absolute nightmare. I ended up making a couple of changes to the adapter plate just to make it a little easier to get a couple of the bolts in and then I found out that with the engine placed in a level position I discovered that the adapter was running into the driveshaft for the front wheel drive. Luckily there was plenty of adapter metal there and I was able to trim off a good sized chunk of it to provide clearance. My next task was setting up and welding in the side engine mounts. Pretty simple affairs that actually use the mounting biscuits designed for a 1932 Ford on a large angle piece of iron plate. Before welding though, I need to fit the exhaust headers and make sure I had clearance room for them. It would have been a real pain to weld those puppies in only to find out that the headers would not clear! With the welding completed, I now had the engine mounted to the chassis. Next things on the list were to start making brackets for the alternator and power steering pump. Basically nothing stock was going to work and all of these parts either had to be hand built or at least modified to work. It took several days to come up with brackets that would do the job and allow the belts to line up properly on the pulleys, then there was the multiple runs to the parts store trying to get the correct length belts to fit those pulleys. Somewhere at some point I think I said hot rodding was fun – I may yet live to retract those words.