Happens when I pull back very slightly on the accelerator due to going down a very slight downgrade. I just pull back ever so slight on the pedal. I'm only pulling back about 5-10%.

Seems like it's loosing spark. The first time it did it I thought I was running out of gas for a second.

Here's my WAG......

How old is the timing chain?

In my mind, I'm picturing when the engine is under load, you've taken up the slack in the chain, but when you 'let up' you're into the slack for a moment.

I had a 360 years ago with high miles on its original chain set, and it had several hesitation/stumble issues that went away with a new chain.

[quote][/quote]Forgot to mention that is has aftermarket electronic ignition under the cap (no points).

Is this a conversion of the old distributor? If so make sure the ground wire from the breaker plate to the housing is intact and good. I had troubles with an Oldsmobile and the breaker plate would intermittently loose ground at various vacuum conditions causing a stumble. As the vacuum advance was working the plate it would loose ground. If it was removed add one and see if it helps.

had a Chrysler electronic ignition pickup coil break the wire internally once, that was a fun one to find

Old distributor with conversion.

Thanks for all the ideas guys. I had to help my daughter move into her first house today so I'll attack this tomorrow.

How confident are you the old and new carbs are set up correctly? .. if you aren't confident, I'm tempted to suspect the carbs..

Can you repeat the problem with the car sitting in your driveway and you manipulate the throttle?
If you can, watch the carb throats and see what the fuel is doing.. Flooding or leaning out?
Or do you HAVE to be on the road.. ?
- Art

lLol. Not laughing at you but with you. Had the Cyclone's engine rebuilt and bought a really nice Quickfuel carb. Nope, that seemed to just go dead at about 2500rpm. Installed a dyno mule Holley that we knew was right, boom, same freaking thing. Finally went with a Holley Sniper EFI system and that took care of the problem. Where was the problem? Not a clue as we replaced the billet distributor, AL box, coil, etc all with Holley gear. Cost plenty to finally get the car running right. Hate to say it but carbs are going to be a thing of the past. Why? Fewer and fewer folks know much about them. Seems like only yesterday that I bought the barracuda and Bee but coming up on 20 years now. I'm will to wager the number of folks that understand(I do) carbs and can fix them(not me apparently) has taken a 50% drop in that time.

I used to rebuild a lot of carbs back in the day, I was the carb rebuild guy in the shop. Its a lot harder to find a good quality carb to rebuild these days because most are getting quite old, throttle bushings are getting bad on most cores. Many of the "new" carbs are not up to the quality the ones from the 60s -early 80s were (and those 80s carbs were very good either), and the current kits leave a lot to be desired as well.

The last vehicle I owned with a carb on it was wrecked in 2011 (nothing to do with the carb). Everything is now EFI and I won't be going back to carbs. Gene