Bogs when accelerating

N2: I just scrapped my 78 Thunderbird with that same engine/trans combo. That sounds like your timing is off. If there are a lot of miles on it, the timing chain could be somewhat stretched. Base line timing should be 12 degrees. Normally, a couple extra degrees will improve things nicely. It sounds like the cab may also be a touch rich. My experience is that I have had to reduce the idle speed at the throttle stop so far the cable sticks a bit because it has never been turned down that far before. Doing that, and I have never had an engine run hot, either. They just return way more mpg than people can believe, even those who see it happening.

 

I hate to say it but I think your timing chain is stretched.:banghead3: This throws off all the other timing including the ignition. You might want to start a tear down on the front end of the engine. It is a lengthy but simple fix. Pretty cheap too.Go find a nice Cloyes double roller and good time to change the cam while your in there:banana:. Something mild and bottom ended torque ranged to haul that beast up the local hills and then take it and ad advance to it to give you even more bottom end. Then you could try that big carb you had on there and see what happens?! Get on the timing so we know where you are in the baseline. Keep me in touch.
Dave.