Need help!! 289 with 351 firing order issues

[Falcon67]

Hi folks, I have a 1967 289 engine restored 8 years ago with a E-Street top end kit from Edelbrock and DUI distributor. I´ve been unable to finish with this car till this year. When we started it we realized that the only firing order that "works" is the one from a 351 and its imposible to set a normal idle. It backfires thru the carb all the time. My suspicion is that maybe the guy from Summit sent a wrong camshaft to the guys who reassembled the engine is 8 years ago. I´ve heard that a 289 can walk with a 351 cam but Im not sure. I also installed a pressure regulator before the carb thinking that the backfire was caused by overpressure. What do you guys think?
Now one of my big doubts is if the 351 distributor gear teeth the same as the 289? Here you can hear it.

View: https://www.youtube.com/watch?v=MABwO_Kz8Rc

Thanks!!

 

[Realmongo]

A 351W cam will work fine in a 289 if the 351W firing order is used.
The distributor gear must be compatible with the cam, or in other words, a cast iron cam needs a cast iron distributor gear, and a steel camshaft needs a steel distributor gear.

 

[Falcon67]

A 351W cam will work fine in a 289 if the 351W firing order is used.
The distributor gear must be compatible with the cam, or in other words, a cast iron cam needs a cast iron distributor gear, and a steel camshaft needs a steel distributor gear.

Thanks! The distribuitor is a Davis Unified and the cam is the one that came with the Edelbrock kit. Are they compatible?

 

[Realmongo]

Thanks! The distribuitor is a Davis Unified and the cam is the one that came with the Edelbrock kit. Are they compatible?

You will need to refer to the manufacturer's webpage for the exact model of the distributor and camshaft to see what material they are made from. When I shifted from the stock Ford cast iron camshaft to an ISKY steel roller camshaft, I had to upgrade my distributor to a 1985 5.0 distributor that had a steel gear to be compatible with the steel roller cam Ford built that year's 5.0 with.