396 engine problem

[rustygmcc20]

so i have a 396 and this is the second time its started doing this but last night when i was pulling into the driveway and stopped the truck the exhaust sounded a little weird kinda like if it was misfiring and sounded like a 6 cyl and the exhaust smelled like gas but i didnt feel like messing with it since it was late and this morning when i go to crank it up it sounds perfectly fine, last time it started doing this i messed with the idle and turned it up and turned it back down and it was fine after that, but that was probably two months ago, im pretty sure its a miss fire but why would it happen every now and then and do any of yall know what the problem could be, sorry the post was so long, but thanks in advance for any advice you may have

[geezer#99]

Could simply be fuel percolation!
When it's hot the fuel gets extremely hot and starts to boil in the carb. It starts flooding a bit. That's why it runs rough and smells rich.
What carb?
What intake?
You got headers?
A stock or different cam?

[61K10]

float set to high? what carb?

[rustygmcc20]

Originally Posted by geezer#99

Could simply be fuel percolation!
When it's hot the fuel gets extremely hot and starts to boil in the carb. It starts flooding a bit. That's why it runs rough and smells rich.
What carb?
What intake?
You got headers?
A stock or different cam?

the carb is a quadrajet, no it doesnt have headers, i couldnt find any numbers to match the casting numbers on the intake manifold but the numbers were 3831067 and below that and a little to the side was T 1, and i have no clue about the camshaft, the guy i bought it from said the original owner rebuilt the motor so i dont know if he used the same cam or used a different one

[rustygmcc20]

Originally Posted by 61K10

float set to high? what carb?

i have no clue about the float but it is a quadrajet

[geezer#99]

So you have a stock bbc. Runs funny when hot (sometimes) and great when cold.
That tells you float is good.
Likely heat percolation.
THere's a couple cures.
A heat plate to isolate the carb from the hot intake. Like this.
http://67-72chevytrucks.com/vboard//...d.php?p=936440

Other thing to check is your initial timing. Retarded timing makes lots of heat.