Help me, I've adjusted the timing but still have a flat spot on my 68 289 from idle to about 3500rpm then it's fine.

 

Sounds like my Mustang, 'cept it only lasts till about 1500 rpm.
Same issue on my '71 F-250 >_<

It goes away completely on the Mustang once it's warm though.

 

Strangely enough after I had her running for little while yesterday it did get a bit better. Given that she is unregistered at the moment I can't rlegally take her for a big drive but I will try and leave her running for while and see what happens. Thanks.

 

my 68 289 was the same...a friend rebuilt the 2 barrel carb for me....it got better, but didn't go away...I just put in a petronix pointless ignition, and it has GREATLY improved the flat spot......it is very very minor at this point...ap

 

Thought I better add a photo of my girl. She is in need of some TLC, but that was one of the reasons I bought her.

[IMG]local://upfiles/66019/1E3D056E4B0941A2821DD1C4CB3816BE.jpg[/IMG]

 

A fellow deuce-panner >_<

 

The flat spot has now moved to 1500rpms. I've put in a new coil and went to gap the points and adjust the dwell and the f0rken points and condenser looked 40 years old. I feel like an idiot. Why would someone change distributor cap, rotor, leads and plugs but not the points (the previous owner). I should have looked at these first. Hopefully this fixes everything. BTW I am working on a Dwell of 30 degrees. Does anyone disagree?

 

According to my Haynes manual, the '68 289 dwell angle is 27. Point gap is 0.021 and the initial timing is 6 degrees BTDC.