testing - Off-Road Forums & Discussion Groups

jeeper2 · #1 08-02-2000, 06:12 PM

Swapping a 360 for a 258

With the help of my moonguy crew [img]/wwwthreads_images/icons/cool.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img][img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/crazy.gif[/img][img]/wwwthreads_images/icons/tongue.gif[/img][img]/wwwthreads_images/icons/wink.gif[/img] my 360 swap is complete. We thought we'd update the 360 Swap Guide by posting what we've learned from out first hand experiences with this swap and posting feedback from others. Our particular swap was a '85 AMC 360 (out of a GW) into an '86 CJ7 with a TF999.

1) Bell Housing:
[img]/wwwthreads_images/icons/cool.gif[/img] All AMC/Jeep V8s and all '72 and later 258 I-6s have the same bell housing pattern and share the same mounting bases.

2) V8 Crankshafts:
[img]/wwwthreads_images/icons/cool.gif[/img] 1966-1971 cranks can be used with torqueflites using a slip-in adapter.
[img]/wwwthreads_images/icons/frown.gif[/img] Most cranks are drilled for a pilot bushing, but check to be sure.

3) Transmissions:
[img]/wwwthreads_images/icons/cool.gif[/img] TH400s handle just about anything you throw at it, but then the moonguys have heard that a built 727 will handle hard downshifts better (like for mud bogging).
[img]/wwwthreads_images/icons/crazy.gif[/img] After 1974 (all CJ7s) the TH400 bolts to the AMC block, but a 0.040-inch spacer is needed, or the front pump will grenade.
[img]/wwwthreads_images/icons/cool.gif[/img] 904/999 OK for 304 or a mild 360... be sure to get the kick down linkage with the 360.
[img]/wwwthreads_images/icons/crazy.gif[/img] 727s from wagoneers can be swapped in for bigger engines, but the clocking is slightly different and the pan is bigger. To clear the front drive shaft from hitting the tranny pan you will need to either; 1) have a lift of 4" or more, 2) install a two piece front drive shaft, or 3) modify the tranny pan. Again, be sure you get the kick down linkage with the 360 (make sure you get all of it).
[img]/wwwthreads_images/icons/cool.gif[/img] '72-'75 T-15 3-spd will easily handle V8 power.
[img]/wwwthreads_images/icons/cool.gif[/img] '72-'79 T-18 4-spd will easily handle V8 power.
[img]/wwwthreads_images/icons/tongue.gif[/img] '80-'86 T-176 is barely strong enough to handle 304/360 power.
[img]/wwwthreads_images/icons/frown.gif[/img] T-4, T-5, and SR5 boxes are not suitable to V8 power.
We're looking for good feedback as to swapper's preferences for clutches to use with manual swaps
[img]/wwwthreads_images/icons/crazy.gif[/img] AMC V8s are externally balanced, so use matching components for vibration dampers, flywheels, and flex plates. If your having trouble finding a 360 flywheel, a 258 flywheel can be rebalanced and used. We noticed a lot of discussion on this topic when the "360 Swap Guide" was first posted on 4/12/00. My advice remains the same... use matching components, then you don't wonder whether or not you did the right thing. 

4) Engine Mounts:
[img]/wwwthreads_images/icons/cool.gif[/img] The right chassis engine mount must be changed for a CJ piece with a 304 V8 (left mount can be retained)
[img]/wwwthreads_images/icons/cool.gif[/img] The mounting brackets on the engine must be changed to '72-'81 CJ pieces for a 304 V8.
[img]/wwwthreads_images/icons/cool.gif[/img] Neoprene mounts must be changed as well and can be found a any local parts house (look for '81 CJ7 with a 304 V8).
[img]/wwwthreads_images/icons/cool.gif[/img] An alternative to the above is MORE's bombproof motor mounts.
 We used a set of older V8 CJ mounts (hard to find) and the frame holes needed to be elongated slightly to match the frame. Other than that, they fit perfectly. [img]/wwwthreads_images/icons/cool.gif[/img]

5) Cooling System:
[img]/wwwthreads_images/icons/cool.gif[/img] I6 radiator outlets match the V8's.
[img]/wwwthreads_images/icons/cool.gif[/img] If you have a I6 heavy duty radiator (3 core) you can reuse.
[img]/wwwthreads_images/icons/cool.gif[/img] A CJ V8 fan shroud must be used, application is for a '81 CJ7 with a 304 V8 (part No. J5355678).
[img]/wwwthreads_images/icons/cool.gif[/img] A CJ factory seven-blade clutch (viscous) fan is best... from V8 or I6 heavy duty cooling package.
[img]/wwwthreads_images/icons/cool.gif[/img] Or you can replace the mechanical fan, with an electric one, and then forget about the shroud (could be cheaper). Electric fan gives a good horsepower gain, and is less stressful on the water pump, especially if in deep water crossings, unless the clutch is in good working order. Install a toggle switch that turns the fan off during water crossings.
 We took our '86 radiator to the radiator shop to get it looked at and we were told it was shot. Why do they call it a radiator repair shop if they don't repair radiators? [img]/wwwthreads_images/icons/mad.gif[/img]. So we went to the local parts store and ordered a new Modine radiator for a '81 CJ7/304 V8/AT/AC combination. We used the CJ factory seven-blade fan, a Flowcooler aluminum water pump from 4WD Hardware. So far, the temp comes up, pegs at operating temp and remains there steady as a rock (even in into the high 90s). [img]/wwwthreads_images/icons/smile.gif[/img]

6) Electrical System:
[img]/wwwthreads_images/icons/cool.gif[/img] Most of I6 wiring harness is compatible, coolant temp sensor wire must be lengthened.
[img]/wwwthreads_images/icons/laugh.gif[/img] TeamRush has pretty much covered the ignition topic in other posts... many thanks Aaron.
[img]/wwwthreads_images/icons/cool.gif[/img] Motorcraft modules work with 6 or 8 cyl distributors.
[img]/wwwthreads_images/icons/frown.gif[/img] Ancillary mountings may need to be changed. Motorola alt. bracket can be drilled out to accept a Delco alt.
 We wired the system using the TR ignition diagram and the '86 CJ7 wiring diagram. However, we found that one of the connectors for the '86 CJ7 ignition module would not fit the generic "blue grommet" ignition module we were using. Luckily we had the Grand Wagoneer's harness to scavenge a plug off of. Other than that, the TeamRush ignition was a breeze. For the TFI coil, we simply modified the stock coil bracket and bolted the TFI coil to it (looks great). Instead of having two 1 1/2 wiring looms running across the back of the firewall, there's one 1" wiring loom... much nicer. [img]/wwwthreads_images/icons/cool.gif[/img]

7) Power Steering:
[img]/wwwthreads_images/icons/crazy.gif[/img] V8 high pressure hose is needed (although some report that the I6 hose works fine). The high pressure hose has a compression fitting for '80 and earlier, and O-ring for '81 and later.
 We used the power steering pump from the I6, and other than having to swap the pulley from serpentine to V-belt, it was easy.

8) Fuel Line:
[img]/wwwthreads_images/icons/crazy.gif[/img] The AMC V8 fuel line is on the driver's side while the I6's in passenger side. A new fuel line will need to be fabricated and re-routed on the left side frame rail, or a fuel line can be pulled off of a 304 powered CJ.

9) Exhaust System:
[img]/wwwthreads_images/icons/crazy.gif[/img] The 2 1/8 inch "Y" exhaust pipe from a 304 powered CJ will take care of the exhaust, IF you can find one and it matches your exhaust manifolds.
[img]/wwwthreads_images/icons/cool.gif[/img] Use 2 1/2 inch pipe from "Y" on out.
[img]/wwwthreads_images/icons/crazy.gif[/img] Try to get manifolds with engine... especially if using earlier rectangular port heads ('66-'69).
[img]/wwwthreads_images/icons/cool.gif[/img] Hedman, among others, makes headers for AMC V8s in CJs. Headman headers that are fender well exit for the 304, will work on the 360, with the automatic, you pretty much have to run side pipes though.
[img]/wwwthreads_images/icons/crazy.gif[/img] A drivers side exhaust manifold from an AMC 304 powered CJ may be required. The CJ manifolds (on my best moonguy information) exit past the block on the right side and between cylinder number 3 and 5 on the left.
 It took several attempts for us to get the exhaust right. Our first attempt was to use the '85 Grand Wagoneer (GW) manifolds which exits "far back" on passenger's side and almost as far back on the driver's side. The driver's side was pretty tight against the firewall, so my moonguys [img]/wwwthreads_images/icons/cool.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img][img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/crazy.gif[/img][img]/wwwthreads_images/icons/tongue.gif[/img][img]/wwwthreads_images/icons/wink.gif[/img] went scavenging and found out that a set of manifolds off of a '74 Wagoneer (no air tubes either) fits pretty nice. The pass side exits pretty much the same as the '85 GW set, but the drivers side exits about 5" forward of the GW set... perfect for my application. [img]/wwwthreads_images/icons/cool.gif[/img] When we took the CJ into the local exhaust shop we ordered a 2 1/8" Y pipe and 2 1/2 from there on out... no cat. However, the TF999 takes up a lot of room, so to avoid some clearance problems we went with a true dual exhaust and economical turbo mufflers... still no cats. The result, sounds throaty without overdoing it... I like it. [img]/wwwthreads_images/icons/cool.gif[/img]

10) Engines:
[img]/wwwthreads_images/icons/cool.gif[/img] '66-'69 AMC V8s have rectangular exhaust ports.
[img]/wwwthreads_images/icons/cool.gif[/img] '70 and later engines have dog-leg exhaust ports (up to 50% better flow, but only a big gain at higher rpms).
[img]/wwwthreads_images/icons/cool.gif[/img] Intake manifolds change with change in exhaust ports '66-'69 and '70 and later take different intakes.
[img]/wwwthreads_images/icons/cool.gif[/img] Combustion chambers differ on earlier heads and heads must be matched to pistons to get correct compression.
[img]/wwwthreads_images/icons/cool.gif[/img] '70-'71 have 50.60 cc (casting No. 319-6291) combustion chambers. Later heads have 57.92 cc combustion chambers.
[img]/wwwthreads_images/icons/crazy.gif[/img] The AMC 258 weighs in at 440 lbs. while the AMC 360 weighs 540. Pre '81 258s weight 90 lbs. more.
[img]/wwwthreads_images/icons/cool.gif[/img] Visually all V8 engine blocks look the same as earlier engines. This means that emissions equipment can be placed on earlier blocks and pass visual inspections.
[img]/wwwthreads_images/icons/cool.gif[/img] Use the wiring diagram for a '80 CJ with a 304 V8, it will be correct for AMC V8 swaps.
[img]/wwwthreads_images/icons/cool.gif[/img] The Computer on later CJs can be taken out.

11) Engine Oiling:
[img]/wwwthreads_images/icons/crazy.gif[/img] AMC V8s tend to starve the rear crankshaft bearings and distributor gears. The solution is to put a TIG welding tip into a oil gallery plug. TeamRush's instructions follow: I drilled the left (odd) bank lifter gallery plug in the front at an angle directed at the fuel pump eccentric and the distributor gear. I threaded the plug, and screwed it back into the block, then screwed a 0.024" mig welder tip into it. When the oil pressure is up, it sprays a continuous stream of oil on the top crankshaft gear. That oil is slung out to the timing chain and applies a continuous supply of oil to the timing chain. When the slots in the gear pass by, (half of the gear is open) the oil stream lands on the distributor gear and fuel pump eccentric, (both of which run virtually dry other wise). I found the Hobart brand of mig tips are made of a better grade of brass, and have convenient flats that help in screwing it in. Entire cost of the upgrade, $2.
[img]/wwwthreads_images/icons/cool.gif[/img] Drilling 1/8 inch holes (chamfer them) in the lifter valley next to the lifter holes will get oil to the cam lobes quicker. My moonguys are wondering how necessary this step is?
[img]/wwwthreads_images/icons/crazy.gif[/img] When you rebuild the oil pump, check the clearances to make sure that they are within specs (.002 or better). Otherwise, you might be wondering why your oil pressure isn't any better than prior to the rebuild when you fire up your new engine. There is an outfit out of Eugene, Oregon called FSRO (541) 461-2335 that reconditions timing covers and sells a gasket kit to achieve necessary clearance. Also, there is a new after market replacement timing cover out on the market, my moonguys say they are back into production after making an improvement to the initial product.
 We used a stock Milodon oil pump rebuild kit, milled the face of the oil pump cover, and checked to make sure it was within tolerances. The result, we get 58 lbs on balmy summer morning starts and a hot idle of 20 lbs. 

12) Miscellaneous Information:
[img]/wwwthreads_images/icons/crazy.gif[/img] The driver's side inner fender well is different between the I6 and V8 CJs. This only makes a difference if you are planning on running an AIR pump with your 360 swap.

13) Practical advice from others:
When you disconnect the old motor, do it at the tranny and not the bellhousing...only 4 bolts.
When setting in the 360, using oem mounts, loosen the left frame rail mount to the end of the threads, set the motor in on that left frame mount and then take the right one and work it onto the frame, put the bolts in, leave them loose work the eng mount onto the frame mount put the nut on it and then tighten the frame rail mounts on both sides.
Put one tire up off the ground a 1/4 inch or so so that when it come time to line up the splines with the clutch you can do it easily by turning the tire.
Take the front end of the Jeep off...6 screws, and you can disconnect the wires at the wire bundle plug on the firewall. We left the front clip on and had no problems getting the engine out or in. 

My mooguys [img]/wwwthreads_images/icons/cool.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img][img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/crazy.gif[/img][img]/wwwthreads_images/icons/tongue.gif[/img][img]/wwwthreads_images/icons/wink.gif[/img] welcome any other moonguy crew with better information to correct them.

'86 CJ7/AMC 360/TR Ignition/T999/D300/OEM D44 rear...[img]/wwwthreads_images/icons/cool.gif[/img]