Bucking at higher RPMs

I recently rebuilt the Rochester 2g carb on my 1970 CJ5 with V6 (recent HEI installation), and am having a hell of a time getting the adjustments right. It runs great at idle and at lower RPMs (like when running around the neighborhood) but runs rough and intermittently bucks very hard when getting up to speed on larger surface streets. When the bucking starts, I clutch and coast to the side of the street. The engine does not die from the bucking, and I can drive home like normal. It scared the hell out of a passenger yesterday.
I have searched the forum for carb adjustment issues, and am now completely confused. Thank you for any help on this issue.
Hugh

 

Do you have a tac? If so then disconnect and try again.

 

Also check the total timing advance. It's not uncommon for an HEI in a oddfire to advance 50 or more deg. at higher rpms. I changed my vacuum advance to an adjustable one from Summit Racing and backed it out all the way. Put a timing light on the engine and see how far advanced it is above 2500 rpms. Do a search for setting up an HEI on the V6. There is lots of info available.

 

Sounds like one of the vacuum retard dizzy is needed, then does it not?

 

Could also be lack of fuel flow - enough for low speed but can't keep up at high speed. Make sure the fuel lines, filters, and pump are good.

 

Thanks for all of the replies, this should keep me busy this weekend. I'll update with any progress.
Hugh

 

No change with the tach disconnected. I will be picking up an adjustable vac advance to try. Some of the fuel lines are soft, I will be replacing these in the next few days. Work has been keeping me busy, but I should have a chance to work on the jeep this weekend.