Thank you Ceej. The rebuild wasn't initially intended but when I pulled the engine out to fix a bad rear main seal shortly after buying it I found cam bearing material all over the inside of oil pan. I installed federal mogul main, rod, and cam bearings. Cleaned up the cam, rebuilt the oil pump, polished up the cylinder walls, new gaskets, rings, timing chain, adjusted the valves, your basic rebuild. Everything was federal mogul or fel-pro, timing chain was a cloyes. Brand new ignition, plugs wires, cap, rotor, and vacuum advance. All borg-warner, and autolite parts. The factory exhaust was replaced with 2 1/2 od pipe.
For the intake the studs are original, the intake hasn't been surfaced, but when I pulled it out this last go around the gasket showed no signs of leaking. The egr had been wiped out prior to my purchasing the car. Someone had cut and beat out the wheel and flap inside the exhaust manifold and replaced it with a bolt and made a block off plate for the intake. For the intake stack everything was installed and torqued to Chilton's standards during my rebuild.
For the carburetor(s) situations, the factory bbd had a badly worn throttle shaft, I blamed all of the engine's problems on this during the first drive home. During the rebuild I looked for a Motorcraft 2100 or a good replacement in the junkyards and that's were the Holley came in. According to other online posts its calculated cfm was slightly smaller than the bbd. It was a good carburetor and it functioned correctly after a thorough rebuild. The stumbling problem made itself known on the first drive with the rebuilt engine. I figured it was the carburetor. Searched a few more junkyards were I came up with a 318 carb that someone had modified to run on a slant. I took the throttle plate off it and put it on the my slant bbd and rebuilt it. It ran but it wasn't right. Took it off and put it to the side. Put the holley back on and tuned it. It fixed some issues but still no luck. So I got a new Summit bbd on loan from a friend and the problem is still there. Pulled the intake checked everything, all the gaskets, the compression of the cylinders, timing, nothing seemed out of place. Put the intake back on it with new seals and played with the timing. Tried a rebuilt Motorcraft carb, still the same problem.
The timing is now set at about 22 degrees, with the Motorcraft carburetor on it. This is the combination the engine as a whole seems to like the best. The hesitation is the smallest its ever been, but it is at a certain throttle position, no longer just off idle and it won't recover from it unless you let up on it or mash the pedal down. Everything I do helps it, but nothing cures it. The initial point were it starts keeps getting pushed back, but the stopping point of the hesitation has remained stationary. All I've been doing is just chasing it around trying to isolate it. Like I said earlier it seems like its "missing" something. It runs too well before and after the hesitation to suggest a major issue.
I wish I knew if it had this problem before, someone swapped that engine in for some reason. I'm starting to think it was for the wrong reason, not to put a good engine in but to pull a good engine out.
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It didn't run quite right but it didn't spark knock either. This engine seems like it is missing something. Ignition possibly? Maybe it needs its egr system? Or it just doesn't have the potential to carry the vacuum it needs... I've never seen anything quite like this. It seems like it has some inherited problem and possibly has never run quite right... I just don't know...
