Almost a year later, the 408 is up and running like a dream. There were so many delays between getting the parts, the engine shop doing the shortblock (see below), and taking on a new job working 50-60 hr weeks.
There were a few issues that I had while installing this motor that are unique to the ZJ. The biggest issue was the crank coming into contact with the oil pan as the ZJ pan is quite shallow at the front of the engine. I ended up swapping on a Durango oil pan which actually fit much better...except for the starter. I had to "modify" the D oil pan with a ball peen hammer and file the starter down a bit to get everything to fit.
A flexplate from a 318 had to be used because I had my rotating assy internally balanced.
I am still in the process of breaking-in the motor, so I haven't been able to get on it much, but I can tell that there's a LOAD of power under my right foot. NOTE: I'm not installing the supercharger until the engine is thoroughly broken in & all the kinks are worked out & I've figured out an axle upgrade. I've been driving around with the gas pushed down around 3/4" (inch, not throttle) & next thing I know, I'm doing 50 on a back road. Silver Bullit was driving along a 2 lane HW next to me & I blew by him with the tach at 3k.
The exhaust at idle is considerably louder...louder than I had noped. Sounds like a muscle car due to the cam (lub, lub,lub,lub), which is awesome, but it's pretty loud when crusing at 50. The motor shakes significantly (makes me want a shaker hood) and the entire cab was as well, but the interior vibrations are now gone since the initial break-in (motor mounts softened up).
Had no codes for the first ~50 miles, but the check engine light came on last night. Around the same time, I had noticed that it started bogging when stepping on it at 2K. I think I may have gotten some oil/dust/coolant in my cat & clogged it up. Getting the PCM scanned this evening.
The APS TC really suprised me a couple of times when I tapped the throttle a little too hard at 3K and it flashed up to 5K in the blink of an eye....not something that I wanted to do while I was breaking it in (OOPS!). Seems like a great unit, though...Thanks Wayne!
What I would have done differently:
Never go to a shop that builds racing engines in July and expect to have your engine before November. There are plenty of guys out there with more money than you who will throw down $15K to have a racing engine built because they just blew theirs.
Because of the new job, I didn't have a lot of time to spend on this project. If I were to do it over again I would have had Hughes Engines, KRC Performance, or Dan "the fastman" Arcand assemble the entire longblock and possibly have one of the latter two shops install and tune the motor if the price was reasonable. Don't get me wrong, Hughes Engines has great parts and their head work is excellent, but they are only an engine shop & I don't know if they would do an install. All the other two guys work on are Magnum motors (...and now the 4.7) from radiator to roll pan, and they really know the Magnum specific stuff.
At idle, the Hughes 55mm circle bore TB sucks so much air through the IAC bore that I get a whistle that sounds a lot like a supercharger. My plan is to radius the edge of the bore a little more to supress the whistle.
Thanks to Nick(Kolak), Wayne440, Chuck(SleepinZJ), Rossi, Silver Bullit, Dave @ Hughes Engines, Marty @ KRC Performance, Dan "the fastman", Chris @ Advanced Racing, and all the guys on MoparChat for helping me bring this together.
P.S. I'll have some pics up later.