efi-diy, I'm with you on most points, and if you were a little closer I'd have a beer with you in person, being in Edmonton. As an auto tech I'm a fan of the 4.2 Atlas but that intake is plain ugly. I understand both sides here and I'm always tempted to look at a FI motor, it's the piecing together a PCM that catches me. I would love to do that swap in my 55 Pontiac as a possibility though, even as I make a post elsewhere about Webber sidedrafts.. I waxed poetic about a 4.2 FI for my 79 1/2 ton and did nothing but now I've got a long term vision type of car that has a future as a long distance cruiser. I am a big fan of modern tech in old cars. I'd love to see your GMC in person some time.
Once you peel off the outer noise insulation and put some paint on the intake - its not so ugly.
The PCM is not a hard one to deal with. Jeremy offers a harness strip/fix and pcm reflash to allow a 4-6 wire connection to the host vehicle.
Alternatively if your going to be modifying the engine and want full access - then Megasquirt 3 or Pro will run the engine using all the stock sensors.
There are intake and exhaust flanges available it you care to roll your own intake/headers.
The one note.. if you are going to use a GM pcm then you MUST keep the drive by wire actuator and integrate it into the throttle blade - otherwise the PCM will shut the engine down.
If is possible to replace the fuel side with a carb - and keep the COP ignition by adding a 36-1 timing wheel on the front then use Microsquirt (its another megasquirt product) to run the coils paired 1/6 5/2 3/4 on the coil trigger input.
So if you wanted to run webber side drafts this would take care of the ign. Prices start at $339 with the short harness.
microsquirt I have a design for the 36-1 trigger wheel/mount plate etc. I have built a few of them ( I needed one for myself before the MS software caught up to use the stock sensors).
All the needed parts to do the install are available except engine mounts. One sore point currently is MT flywheels. Its being worked on but slow.
