The Dodge Challenger Message Board

my rebuilt 340 has a hard time starting! if i shut it down and then restart right away it starts fine but if it sits about 10 minutes I have to give it some gas and then hold it to the floor until it start about 10 to 20 seconds of turning it over. I have relocated the fuel filter away from the edelbrock intake. the timing seems to be within reason. it has a new 600cfm edelbrock carb. do you think a carb spacer might help of maybe it has a weak coil. It has new point rotor and cap. would the dwell setting have any effect with this problem????

It is heat soaking into the carb from the engine that is causing this most likely.

Try this first. When starting from hot after it has stood for a few mins try not to touch the accelerator pedal at all when cranking. If the fuel is boiling in the carb it can drip into the intake causing it to be rich. If you touch the throttle at all before it fires you will be squirting more fuel down there that will flood the engine. Holding the throttle to the floor while cranking clears the flooded condition.

If it will not hot start even without you touching the throttle then you need to find ways to keep the carb cooler. Blocking off the heat riser through the intake is an easy way to do this and it will also add power to the engine. A spacer under the carb would be my next step.

I blocked the heat riser and got a 1 inch carb spacer it still does not want to start unless I hold the pedel to the floor. this is after it sits for about an hour after driving at running temp. Do you think I should adjust the floats so less fuel is in the carb?

I wouldn't. The fuel level in the carb is quite critical. It should only be adjusted to the correct level.

Is the choke closing when the engine is still hot? Electric choke?

Maybe a fuel leak into the intake from the carb?