Hiya,

I got a timing problem that's just racking my brains out.

I got a 350 small block that's spitting through the carb especially when cold.

The crank timing is 10 BTDC
The cam is a Lunati bare bones , the middle one of a selection of 3 offers hafta find specs but it works between 1500 to 5500 RPM. Sprocket set to stock.
The timing chain is a fresh true double roller.
The distributor is a street fire with moroso centrifugal weights Springs start at 6 degrees at 1500 RPM and max out to 23 degrees at 3000 RPM.
I found by accident that I have an adjustable vacuum advance set loose as possible so it don't max out so quick.
The spark comes from a street fire external box similar to a MSD but cheaper. Multi spark.
The wires are Taylor 8mm silicone and loomed. There is no arcing between wires or anything I checked at night. Besides it fires on all 8.
Carb is a tuned edelbrock 1406. Perfect mixture all the way.
Fuel pump is a regulated Big End mechanical. Pressure set a 6.5 PSI to help feed the nitrous solenoid.
Air cleaner is a K&N with the element top.
Heads are World sportsters with 202,150 valves and 71cc chambers i think.
Pistons are 030 over TRW flat tops. Compression is between 9-10 to 1.
Flow tech headers with 2-12 pipes with flow master knockoff mufflers and crossover pipe.
I had the car om a dyno and it has 236 HP at the wheels at 10 BTDC I gain 1 horsepower at 11 BTDC. Only change was setting the accelerator pump at max squirt.

The spark spits through the carb at 34 throttle and stalls from idle to WOT every time. Idle set at 650 RPM. Cold weather aggravates the problem.

Occasional backfire when drag racing. In fact in 2 years it only did it twice.

Yes, I checked the cap, rotor, weights, wires, plugs, timing chain slop vacuum advance, hoses,
Other than slight rust spot on centrifugal weight post I didn't find anything wrong.

Anyway, i'm out of ideas, does anyone have a clue?