It's been awhile since I put this thing on hold, but I'm kind of thinking about giving it a whirl again.
I got to thinking....
What if the guy who replaced the injectors (cyl 3&4) had switched the injector wires so they were firing out of order?
I've been assuming all along he did it right, but what if he didn't?

What if the injectors are dumping fuel at the wrong time, and it's being ignited on the wasted spark, or maybe not at all.
It would certainly explain it running like crap and the gassy smell at the exhaust, eh?

 

It's bank-fired, it wouldn't matter.

 

I'm an old school kinda guy.
Spark, fuel, and air....

Sorry to appear dumb.
What is bank fired?

 

In bank-fired EFI Ford V8s of this era, each time one injector in one of the banks (cyl 1-4, 5-8) is fired, all of them in that bank are fired - but only half a dose each time. Modern multiport EFI is worlds better but this is how it began.

Read more about it here:

https://forums.holley.com/showthread...amp-Paired-EFI

 

Well, I guess that shoots the crap out my theory.

 

Well, I hate to see empty ended threads on sites like these, so I'm going to try to wrap it up.

I had a guy who was supposed to be a real stand up guy, and great mechanic look at the thing.
His great idea was to convert it to carb. (There's another thread on that.)

That job went to hell shortly after he started it.
He removed a bunch of stuff from the top of the engine, replaced the intake with one from the boneyard, then could just never find the time or ambition to finish the job in what I thought was a fair timeline.

Before tearing it down, I suggested we take a compression test just to see. A few cylinders were almost 30 psi lower than the others.

I made the decision to screw the whole thing, and take it to a shop to have a new (Jasper) engine installed, and put back to stock.
While picking up all the pieces before sending it off, I found the real culprit.

Out of 3 guys who worked on it, and two who had the plenum off, no one bothered to notice the melted injector harness.
I peeled the burned part back, and sure enough, three wires had been shorted together during the small fire.
Oh well. Nonetheless, the engine was getting tired and had 100K or maybe even 200K on it. No telling when the odometer only goes to 99999.

So I had a shop install the engine, and while doing so, replace just about anything they could with new; ie alternator, starter, radiator, etc. etc.
It's gonna cost a bundle, but other than oil changes and maint. my hope is to not have to worry or open the hood for some time to come.
I'll pick it up tomorrow, then begin a few projects like a new master cylinder and maybe some brakes and shocks.