It's been awhile since I posted (crazy busy with work, house, getting married, etc.) and I ended up keeping my Challenger with a Eddy headed 408 small block. A few years back I was seriously considering selling it but couldn't do it. I've had it since I was 16. Anyway, I'm now in the process of modernizing and restoring the car. I've already switched to 1970 style bumpers and brackets and a dual exhaust valence. The rest of the body/paint will be done at a later date.
Engine wise, I ditched the Edelbrock 800 carb and Air Gap intake for a Super Victor EFI manifold, Edelbrock 4 hole throttle body, and some 44lb Venom Injectors in port fuel injection configuration. It's all fed from a tank mounted Aeromotive Phantom Stealth 340 pump.
Controlling everything is a Megasquirt 2 ECU that I built and modified myself. This thing is awesome, and I would do it all over again in a heartbeat. It is extremely universal and configurable, both from a hardware and software standpoint. It controls the following:
fan
PWM IAC
Injectors in Bank Batch fire
A/C Compressor
Ignition Coil
fuel pump relay
tachometer output
This winter I'll probably ditch the distributor entirely and fit a crank trigger and coil packs instead. The wiring and Megasquirt modifications are already in place for it. I also plan on adding a knock sensor.
I ended up building a harness from scratch since virtually everything else in my car is not stock after installing a Painless Wiring 18 circuit harness and a ton of other modern conveniences. I use a pair of 35 pin Ampseal connectors on an aluminum bulkhead plate I fabricated and mounted in the stock location. The black one is for the chassis wiring and the blue for the EFI system. The Megasquirt is located behind the glove box.
All I can say is, wow! I wish I had went EFI sooner. With minimal tuning I have this car running far better than it ever did with a carb. It'll idle in closed loop baby smooth at 800RPM despite the cam, and idles up on cold start or when the A/C is on like a new car. She fires up instantly and doesn't stumble or buck at all if driven cold. It is almost odorless now when idling, where as before it was smelly! It has built in rev limiter (can be set up to vary with engine temp, so lower rev limit when cold) and launch control functions. Here are some screenshots of the tuning and datalogging software. It's pretty powerful stuff and I've done calibration work for late model engines at the OEM level with Engineering level calibration software.
Cruising is incredible too. This car will run as lean as 16.5-17.0:1 without an issue, and I am still playing with advance to see how much I can squeeze out of it. I've already noticed a huge difference in MPG. Throttle response and part throttle are incredible as well. I need to get it on a dyno to really dial in the WOT and spark tables still. I'm running a wideband in each bank and pull crank signal off of the VR sensor in the locked out MSD distributor. With a few mods (shaft collar on the distributor shaft and chain tensioner) the timing is actually pretty steady.
Admittedly, I'm not a carb tuning pro, but I'm not that bad either.
Last week, I installed a Vintage Air A/C system. It works incredibly well and I'd recommend it to anyone. The fitment is pretty good, the box is tiny in comparison to the factory stuff, and it blows like ice. I did not use their compressor kit since I have a March serpentine drive, so I fitted a compressor to that instead. It makes the car much more usable since I no longer have to wait for the perfect day to cruise in it without being baked alive. Low speed cooling is an issue if I idle for a long time, but that rarely happens so I don't think I'll be doing anything about it. The HHR fan cools quite well for the most part.
This car is infinitely more enjoyable now, and I cannot wait to get the body/paint done so it looks as good as it drives. I'm planning on going to modern suspension, brakes, and a 6 speed too. If I can get low to mid 20's MPG out of this thing I'll drive it daily!
