We always have the same thought before undertaking any major drivetrain change. "How hard can it be?" This was especially true with our 4.0L swap in this '68 J2000. And while actually bolting in the 4.0L, NV3550, and NP208 went down without drama, we got complacent and some of the little stuff bit us in the ass.
Ideally, we'd have a full road report ready for you in this installment. We used stock XJ engine-to-frame fuel lines from a junkyard XJ and tied them to the fuel pump and filter setup we obtained from Hesco. The Hotwire Auto wiring harness is hooked up and the factory ECU is plugged in. We bolted an XJ gas pedal to the firewall to facilitate the XJ throttle cable we used.
In this installment we're putting the wraps on our cooling system, using our trusted electric fan of choice for most CJ and FSJ radiators, the Flex-a-lite PN 575. We also added power steering with some junkyard parts, and tapped one of our favorite driveshaft builders, Tom Wood, for some trick, high-quality driveshafts that will spin well and true for the life of this vehicle.
So, then what's the holdup? Why no road test? As it turns out, the NP208 we bought on-line and had shipped from the Midwest was rife with hairline cracks. As soon as we disengaged the parking brake and allowed the vehicle weight to rest on the T-case yokes, those little hairlines turned into big, leaky spiders. It's so bad we're convinced if we put any power to the T-case it would literally blow apart. So, while we're searching for a replacement NP208 we'll turn our attention to improving the condition of the interior for our next installment.
 We then put in a call to Tom...  We then put in a call to Tom Wood's Custom Drive Shafts. For high quality and no drama, there's no better game in town. Wood hooked us up with his special front driveshaft with a Spicer-type 1310 CV that mates to the Saginaw flange. Unlike the Saginaw shaft (bottom, shown at full flex), Wood's hybrid Spicer CV will flex to nearly 35 degrees before binding. Wood also sent out the correct yokes to convert the front Dodge Dana 44 and the rear of the Dodge NP208 to a standard Spicer 1310 yoke. |  We mentioned in a previous...  We mentioned in a previous installment the need to address a wide gap between the front T-case driveshaft flange and the transmission crossmember. To bump the front driveshaft a little farther forward and allow more droop without driveshaft-to-crossmember interference, we ordered a Superlift 1-inch driveshaft spacer, PN 4310. |  Here you can see the increased...  Here you can see the increased droop afforded by the special Tom Wood's Custom Drive Shafts Saginaw/Spicer hybrid CV and the crossmember clearance gained from the 1-inch Superlift driveshaft spacer. Our front shaft has way more droop than our front suspension can supply. And naturally, our 1310 rear driveshaft plunked right in after we swapped out the rear oil seal and yoke on the Dodge NP208 T-case. |
 Although it looks like snot,...  Although it looks like snot, our factory '68 radiator was in good shape and will offer more than enough cooling to handle the 4.0L. We chose to forgo the hassle of swapping our offset XJ mechanical fan to a centered Wrangler fan assembly. Instead, we're running a Flex-a-lite PN 575 twin 12-inch electric fan. |  Designed to mount to a '72-'86...  Designed to mount to a '72-'86 CJ radiator, the Flex-a-lite PN 575 fits very nicely to an FSJ radiator with some slight redrilling and oblonging of the aluminum mounting bracket holes. The twin 10-blade, 12-inch fans move 2,500cfm with a 19.5 amp draw at full power. We hooked up the supplied thermostat controller and wired it up following Flex-a-lite's instructions. |  Another thing that needed...  Another thing that needed addressing on our manual steering truck was the fact that we couldn't disconnect the power steering pump thanks to the 4.0L's serpentine belt assembly. Cappa has been told by Chrysler engineers it's safe to hook up the pressure and return lines to bypass the steering box, but we found it easier to simply nab a stock steering box and pitman arm from a '91 XJ at the junkyard. |
 The 4.0L and the 232/258 engine...  The 4.0L and the 232/258 engine family have very similar architectures. While we were able to use the upper radiator hose from the 232, the lower was different. Rather than make a parts store run, we used a short length of exhaust tubing we had laying around and cut and sleeved a lower radiator hose that fit. |  After reaming the pitman arm...  After reaming the pitman arm to accept our Parts Mike 1-ton GM drag link tie rod, we bolted the XJ box to the frame. The stock FSJ steering shaft coupler slid right onto the XJ box's input splines and the 4.0L power steering pressure line reached with no hassle. We did have to lengthen the return line to reach without bending. The drag link angle with the XJ pitman arm is ideal. | |