my truck backfires thru the carburetor when i press the pedal all the way to the floor,i was told that it was a intake valve

 

Close enough. If it backfires through the carburetor, you have timing issues.

 

ok ,i have a question im no mechanic,but why couldn't it be the intake valve ,and why do you say the carburetor

 

Because you said it's backfiring through the carburetor?

It could be an sticking/dead intake valve, but more often than not, the timing is out of adjustment.

 

one more thing ,when i turn the key to start the engine,it fires right up every time

 

if its a sticky valve ,how can you fix that,do they sell something in the auto parts store

 

If it's a sticky valve, you have to find the exact valve that is malfunctioning. Then you remove the head(s) and repair.

 

ok thank you ,im going to check the timing 1st,thanks again

 

Could be running too lean as well.

 

too lean meaning not enough gas

 

That's correct, i'm not saying it couldn't be a sticky valve but a lean condition can cause a "popping" throught the carb too, just something to consider.

 

thank you, i'm going to adjust the carb,i just want that backfiring gone

 

isn't there some products that will fix a sticky valve problem

 

okay ,i installed a vacuum gauge and it showed that my timing is good but needle was moving quite a bit back and forth ,does that mean its a valve,also how can you locate the bad valve in which cylinder,the motor misses a little,now if i have a bad valve would i still have compression on that cylinder

 

I would look at a lean carb.
fuel filter stopped up
dirt in needle valve
float level too low