My 1600dp running kadrons is backfiring once it is warmed up and only at idle... Had the valves dine and timing set.. Wondering what it could be , any help please

is it backfiring out of the tail pipe or the carbs? your carbs probably are out of sync

could be too lean, in which case you would have lean misfires during idle.
Or, if its way too rich, unburnt fuel will accumulate in the exhaust and occationally ignite.
Your problem is most likely fuel related though, and on or the other of the above.

It's popping out of the tailpipes.. Last night when I had to open my garage , it was shooting short bursts of fire out of the tailpipes .. Just don't wanna tear up my new motor ... Any1 good with tuning carbs/sync.. I'd gladly pay .. Thanks

I may be able to swing by and give you a hand. You're on the SE side somewhere, right?

You need to re run your valves and check your timing.. First and foremost..

Yea I'm in deer park right by 225&beltway8

all I am gonna say... crossed wires...

Just kidding but that could be an over looked issue...

I was thinking spark plug wires too, but it runs fine except idle. The carbs are probably just way out of adjustment/sync.