Swapping in a 360 Engine
If you want more power, the way to get the most bang for your buck with the least amount of hassle is to drop in a 360. You can't go wrong.
318s can be modified for more horsepower. They are great for lighter cars, and shouldn't be discounted for one minute. Bob Mazzolini has a 1985 318 in a 2000 Chrysler Sebring
race car that runs in the 10s. However, that's in a 3100lb race car with 5.87 rear gears. For a high performance 318 in a heavy 3600-3700lb car like an M-body, you will need a big cam, taller gears and a looser converter. After all that you will have an engine that is not very streetable. It will be a dog in traffic and it will definitely not be very emissions-friendly. For moving heavy M-bodies around, the key word is TORQUE - not horsepower, and a 360 wins hands down. A 360 will have more low end grunt due to its longer 3.58" stroke. 318's have a shorter 3.31" stroke, so for any given engine speed (RPM), they will provide less torque than a 360. A 360 is also great for a relatively mild, low buck setup, much like Mike has. It will outrun a tweaked 318 all day long. What is Needed to Swap in a 360
Excerpts from Old Threads:
- Oil pan: If you don't have a donor passenger car 360 center sump oil pan, you will need to get one. A truck 360 oil pan won't work in a car, and a 318 pan won't fit a 360. Get the Mopar Performance 360 Center Sump Passenger Car Oil Pan Kit (P5249059), which includes the pan, pick up, dipstick & tube. Mancini Racing - MOPP5249059.
- Torque converter: 318s are internally balanced. 360s are externally balanced. A 318 torque converter will not work with a 360 because it doesn't have the necessary balance weights on it. You have two options: Keep your stock converter and replace your stock flexplate with a B&M weighted flexplate, also available from Mancini. There is one version for the 727 (10236) and one version for the 904 (10239). The B&M piece is weighted to allow you to use your existing 318 neutrally balanced converter. Your other option is to keep your stock flexplate and take your torque converter to a transmission shop and have the correct weights welded on for the 360. Mopar Performance sells a kit which has the two weights and the template showing where to place them:MOPAR Balance Weight Package
- Harmonic balancer or damper: You must use one for a 360. The 318 damper will not work.
- Motor mounts: The driver's side block mounting bosses on a 360 are closer together than those on a 318. This means that your 318 driver's mount will not bolt tightly to the 360 mounting bosses unless you use some spacers (a few washers) to make up the difference. No big deal. You can also buy the correct 360 F/J/M mounts from
Schumacher, but they are spendy.
- Intake: If you have a stock 2-barrel 318 intake with the Lean Burn, it will choke a 360 with its small ports, so you will need to go with a cast iron 4-barrel cop car, truck or van intake or an aftermarket unit. You will need the cop car 4-barrel linkage to go with this. If you have a cop car with 4-barrel intake, you can just swap it over to the 360 since cop car 318s have 360 heads.
- Ignition: The Lean Burn computer setup should go since it wasn't designed to work with a 360, and it is not worth adapting anyway. A better bet is the Electronic Conversion Kit from Mopar Performance
- Exhaust: Later 318s have exhaust manifolds that are the same size as 360 ones. However, the 360 manifolds exit in a different spot so if you don't plan on doing anything with the exhaust, you'll have to keep the manifolds you're using now. If you don't have a visual emissions inspection, you can swap to a non-precat y-pipe (Maremont #440047) which will help. You can also get a set of headers for an F-body (Aspen/Volare). Hooker Comps (not Super Comps), Hedmann and Summit brand are said to work well.
- Transmission: You have a lock-up style 904 transmission. The 360 will have lots more torque than the 318 and the lock-up assembly won't take much abuse. You will either have to baby it or upgrade to a non-LU 727 transmission. You dont have to do anything different to put in the 727 except get the drive shaft shortened and get the correct pivot bracket and kickdown lever for it. If it's presently a 2-barrel, you need the different top kickdown linkage too and the 4-barrel bracket that the throttle cable clamps to.
- Rear: You probably have the stock 7.25" rear, which will break if you look at it too hard. You should seriously think about upgrading to an 8.25" cop car unit, which will drop right in. Be sure to check the ratio first to avoid getting one of the dog ratios like 2.24:1. The one to look for is 2.94:1.
- Driveshaft: If you upgrade to a 727/8.25", you will either have to find a driveshaft for a 727/8.25" equipped M-body, or have it cut and rebalanced by a truck shop. If you keep the 904 and go with the 8.25", try to find the driveshaft that came from the donor cop car. It should fit. Otherwise, have it cut as mentioned above. If you keep the 904 and the 7.25", no driveshaft changes are needed. Just connect it back together and wait for either the 904 or the 7.25" to go "boom"! Make sure that you replace all of the u-joints while the driveshaft is out.
- Cooling: Some board members have swapped in a 360 with the stock radiator and encountered no problems. The 360 is bigger inside than a 318, so it won't hurt to add more capacity to your cooling system. A good solution (posted by Thunderstruck), is to use a 3-row radiator for an 87 Dodge Ram Pickup 360. He has done this swap and it will bolt right in. The shroud fits too. See the Library topic here.
- Accessories: All the 318 accessories on the front of the engine will bolt right up to the 360.
- Mike: "If you want good gas mileage at all, you might as well forget about the 360. Theres a reason why they stopped using them."
- Mydodgedip: "While the engine is out, consider if anything else under the hood needs to be changed regardless of what engine is in it. Battery tray rotted? Gearbox loose? leaky radiator? Etc. Theyre all easier to change while the engine is out!"
- A 318 mount adapted with a spacer to fit a 360 block. (Courtesy of Mopar Muscle magazine)
- 360 oil pan on the left and a 273/318/340 oil pan on the right. (Courtesy of Car Craft magazine)
- Compiled from numerous posts by Farley's members
- Mopar Muscle Magazine "Stealth Bomber" 360 swap. The Diplomat featured in this article is now owned by member Black88.